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Abbreviations, acronyms and symbolic representations are very much part of the language of peptide science in conversational communication as much as in its literature. They are not only a convenience, either they enable the necessary but distracting complexities of long chemical names and technical terms to be pushed into the background so the wood can be seen among the trees. Many of the abbreviations in use are so much in currency that they need no explanation. The main purpose of this editorial is to identify them and free authors from the hitherto tiresome requirement to define them in every paper. Those in the tables that follow which will be updated from time to time may in future be used in this Journal without explanation.

All other abbreviations should be defined. Previously published usage should be followed unless it is manifestly clumsy or inappropriate. Where it is necessary to devise new abbreviations and symbols, the general principles behind established examples should be followed. Thus, new amino-acid symbols should be of form Abc, with due thought for possible ambiguities (Dap might be obvious for diaminoproprionic acid, for example, but what about diaminopimelic acid?).

Where alternatives are indicated below, the first is preferred.

Proteinogenic Amino Acids 
Ala Alanine 
Arg Arginine 
Asn Asparagine 
Asp Aspartic acid 
Asx Asn or Asp  
Cys Cysteine 
Gln Glutamine 
Glu Glutamic acid 
Glx Gln or Glu  
Gly Glycine 
His Histidine 
Ile Isoleucine 
Leu Leucine 
Lys Lysine 
Met Methionine 
Phe Phenylalanine 
Pro Proline 
Ser Serine 
Thr Threonine 
Trp Tryptophan 
Tyr Tyrosine 
Val Valine 
Proteinogenic Amino Acids 
Ala Alanine 
Arg Arginine 
Asn Asparagine 
Asp Aspartic acid 
Asx Asn or Asp  
Cys Cysteine 
Gln Glutamine 
Glu Glutamic acid 
Glx Gln or Glu  
Gly Glycine 
His Histidine 
Ile Isoleucine 
Leu Leucine 
Lys Lysine 
Met Methionine 
Phe Phenylalanine 
Pro Proline 
Ser Serine 
Thr Threonine 
Trp Tryptophan 
Tyr Tyrosine 
Val Valine 

Copyright © 1999 European Peptide Society and John Wiley & Sons, Ltd. Reproduced with permission from J. Peptide Sci., 1999, 5, 465471.

Aad α-Aminoadipic acid 
βAad β-Aminoadipic acid 
Abu α-Aminobutyric acid 
Aib α-Aminoisobutyric acid; α-methylalanine 
βAla β-Alanine; 3-aminopropionic acid (avoid Bal) 
Asu α-Aminosuberic acid 
Aze Azetidine-2-carboxylic acid 
Cha β-cyclohexylalanine 
Cit Citrulline; 2-amino-5-ureidovaleric acid 
Dha Dehydroalanine (also ΔAla) 
Gla γ-Carboxyglutamic acid 
Glp pyroglutamic acid; 5-oxoproline (also pGlu) 
Hph Homophenylalanine (Hse=homoserine, and so on). Caution is necessary over the use of the prefix homo in relation to α-amino-acid names and the symbols for homo-analogues. When the term first became current, it was applied to analogues in which a side-chain CH2 extension had been introduced. Thus homoserine has a side-chain CH2CH2OH, homoarginine CH2CH2CH2NHC(NH)NH2, and so on. In such cases, the convention is that a new three-letter symbol for the analogue is derived from the parent, by taking H for homo and combining it with the first two characters of the parental symbol hence, Hse, Har and so on. Now, however, there is a considerable literature on β-amino acids which are analogues of α-amino acids in which a CH2 group has been inserted between the α-carbon and carboxyl group. These analogues have also been called homo-analogues, and there are instances for example not only of ‘homophenylalanine', NH2CH(CH2CH2Ph)CO2H, abbreviated Hph, but also ‘homophenylalanine', NH2CH(CH2Ph)CH2CO2H abbreviated Hph.Further, members of the analogue class with CH2 interpolated between the α-carbon and the carboxyl group of the parent α-amino acid structure have been called both ‘α-homo'- and ‘β-homo’. Clearly great care is essential, and abbreviations for ‘homo’ analogues ought to be fully defined on every occasion. The term ‘β-homo’ seems preferable for backbone extension (emphasizing as it does that the residue has become a β-amino acid residue), with abbreviated symbolism as illustrated by βHph for NH2CH(CH2Ph)CH2CO2H. 
Hyl δ-Hydroxylysine 
Hyp 4-Hydroxyproline 
αIle allo-Isoleucine; 2S, 3R in the l-series 
Lan Lanthionine; S-(2-amino-2-carboxyethyl)cysteine 
MeAla N-Methylalanine (MeVal=N-methylvaline, and so on). This style should not be used for α-methyl residues, for which either a separate unique symbol (such as Aib for α-methylalanine) should be used, or the position of the methyl group should be made explicit as in αMeTyr for α-methyltyrosine. 
Nle Norleucine; α-aminocaproic acid 
Orn Ornithine; 2,5-diaminopentanoic acid 
Phg Phenylglycine; 2-aminophenylacetic acid 
Pip Pipecolic acid; piperidine-s-carboxylic acid 
Sar Sarcosine; N-methylglycine 
Sta Statine; (3S, 4S)-4-amino-3-hydroxy-6-methyl-heptanoic acid 
Thi β-Thienylalanine 
Tic 1,2,3,4-Tetrahydroisoquinoline-3-carboxylic acid 
αThr allo-Threonine; 2S, 3S in the l-series 
Thz Thiazolidine-4-carboxylic acid, thiaproline 
Xaa Unknown or unspecified (also Aaa) 
Aad α-Aminoadipic acid 
βAad β-Aminoadipic acid 
Abu α-Aminobutyric acid 
Aib α-Aminoisobutyric acid; α-methylalanine 
βAla β-Alanine; 3-aminopropionic acid (avoid Bal) 
Asu α-Aminosuberic acid 
Aze Azetidine-2-carboxylic acid 
Cha β-cyclohexylalanine 
Cit Citrulline; 2-amino-5-ureidovaleric acid 
Dha Dehydroalanine (also ΔAla) 
Gla γ-Carboxyglutamic acid 
Glp pyroglutamic acid; 5-oxoproline (also pGlu) 
Hph Homophenylalanine (Hse=homoserine, and so on). Caution is necessary over the use of the prefix homo in relation to α-amino-acid names and the symbols for homo-analogues. When the term first became current, it was applied to analogues in which a side-chain CH2 extension had been introduced. Thus homoserine has a side-chain CH2CH2OH, homoarginine CH2CH2CH2NHC(NH)NH2, and so on. In such cases, the convention is that a new three-letter symbol for the analogue is derived from the parent, by taking H for homo and combining it with the first two characters of the parental symbol hence, Hse, Har and so on. Now, however, there is a considerable literature on β-amino acids which are analogues of α-amino acids in which a CH2 group has been inserted between the α-carbon and carboxyl group. These analogues have also been called homo-analogues, and there are instances for example not only of ‘homophenylalanine', NH2CH(CH2CH2Ph)CO2H, abbreviated Hph, but also ‘homophenylalanine', NH2CH(CH2Ph)CH2CO2H abbreviated Hph.Further, members of the analogue class with CH2 interpolated between the α-carbon and the carboxyl group of the parent α-amino acid structure have been called both ‘α-homo'- and ‘β-homo’. Clearly great care is essential, and abbreviations for ‘homo’ analogues ought to be fully defined on every occasion. The term ‘β-homo’ seems preferable for backbone extension (emphasizing as it does that the residue has become a β-amino acid residue), with abbreviated symbolism as illustrated by βHph for NH2CH(CH2Ph)CH2CO2H. 
Hyl δ-Hydroxylysine 
Hyp 4-Hydroxyproline 
αIle allo-Isoleucine; 2S, 3R in the l-series 
Lan Lanthionine; S-(2-amino-2-carboxyethyl)cysteine 
MeAla N-Methylalanine (MeVal=N-methylvaline, and so on). This style should not be used for α-methyl residues, for which either a separate unique symbol (such as Aib for α-methylalanine) should be used, or the position of the methyl group should be made explicit as in αMeTyr for α-methyltyrosine. 
Nle Norleucine; α-aminocaproic acid 
Orn Ornithine; 2,5-diaminopentanoic acid 
Phg Phenylglycine; 2-aminophenylacetic acid 
Pip Pipecolic acid; piperidine-s-carboxylic acid 
Sar Sarcosine; N-methylglycine 
Sta Statine; (3S, 4S)-4-amino-3-hydroxy-6-methyl-heptanoic acid 
Thi β-Thienylalanine 
Tic 1,2,3,4-Tetrahydroisoquinoline-3-carboxylic acid 
αThr allo-Threonine; 2S, 3S in the l-series 
Thz Thiazolidine-4-carboxylic acid, thiaproline 
Xaa Unknown or unspecified (also Aaa) 

The three-letter symbols should be used in accord with the IUPAC-IUB conventions, which have been published in many places (e.g. European J. Biochem. 1984; 138: 937), and which are (May 1999) also available with other relevant documents at: http://www.chem.qnw.ac.uk/iubmb/iubmb.html#03

It would be superfluous to attempt to repeat all the detail which can be found at the above address, and the ramifications are extensive, but a few remarks focussing on common misuses and confusions may assist. The three-letter symbol standing alone represents the unmodified intact amino acid, of the l-configuration unless otherwise stated (but the l-configuration may be indicated if desired for emphasis: e.g.l-Ala). The same three-letter symbol, however, also stands for the corresponding amino acid residue. The symbols can thus be used to represent peptides (e.g. AlaAla or Ala-Ala=alanylalanine). When nothing is shown attached to either side of the three-letter symbol it is meant to be understood that the amino group (always understood to be on the left) or carboxyl group is unmodified, but this can be emphasized, so AlaAla=H-AlaAla-OH. Note however that indicating free termini by presenting the terminal group in full is wrong; NH2AlaAlaCO2H implies a hydrazino group at one end and an α-keto acid derivative at the other. Representation of a free terminal carboxyl group by writing H on the right is also wrong because that implies a terminal aldehyde.

Side chains are understood to be unsubstituted if nothing is shown, but a substituent can be indicated by use of brackets or attachment by a vertical bond up or down. Thus an O-methylserine residue could be shown as 1, 2, or 3.

graphic

Note that the oxygen atom is not shown: it is contained in the three-letter symbol showing it, as in Ser(OMe), would imply that a peroxy group was present. Bonds up or down should be used only for indicating side-chain substitution. Confusions may creep in if the three-letter symbols are used thoughtlessly in representations of cyclic peptides. Consider by way of example the hypothetical cyclopeptide threonylalanylalanylglutamic acid. It might be thought that this compound could be economically represented 4.

graphic

But this is wrong because the left hand vertical bond implies an ester link between the two side chains, and strictly speaking if the right hand vertical bond means anything it means that the two Ala α-carbons are linked by a CH2CH2bridge. This objection could be circumvented by writing the structure as in 5.

graphic

But this is now ambiguous because the convention that the symbols are to be read as having the amino nitrogen to the left cannot be imposed on both lines. The direction of the peptide bond needs to be shown with an arrow pointing from CO to N, as in 6.

graphic

Actually the simplest representation is on one line, as in 7.

graphic

Substituents and Protecting Groups
Ac Acetyl 
Acm Acetamidomethyl 
Adoc 1-Adamantyloxycarbonyl 
Alloc Allyloxycarbonyl 
Boc t-Butoxycarbonyl 
Bom π-Benzyloxymethyl 
Bpoc 2-(4-Biphenylyl)isopropoxycarbonyl 
Btm Benzylthiomethyl 
Bum π-t-Butoxymethyl 
Bui i-Butyl 
Bun n-Butyl 
But t-Butyl 
Bz Benzoyl 
Bzl Benzyl (also Bn); Bzl(OMe)=4-methoxybenzyl and so on 
Cha Cyclohexylammonium salt 
Clt 2-Chlorotrityl 
Dcha Dicyclohexylammonium salt 
Dde 1-(4,4-Dimethyl-2,6-dioxocyclohex-1-ylidene)ethyl 
Ddz 2-(3,5-Dimethoxyphenyl)-isopropoxycarbonyl 
Dnp 2,4-Dinitrophenyl 
Dpp Diphenylphosphinyl 
Et Ethyl 
Fmoc 9-Fluorenylmethoxycarbonyl 
For Formyl 
Mbh 4,4′-Dimethoxydiphenylmethyl, 4,4′-Dimethoxybenzhydryl 
Mbs 4-Methoxybenzenesulphonyl 
Me Methyl 
Mob 4-Methoxybenzyl 
Mtr 2,3,6-Trimethyl,4-methoxybenzenesulphonyl 
Nps 2-Nitrophenylsulphenyl 
OA11 Allyl ester 
OBt 1-Benzotriazolyl ester 
OcHx Cyclohexyl ester 
ONp 4-Nitrophenyl ester 
OPcp Pentachlorophenyl ester 
OPfp Pentafluorophenyl ester 
OSu Succinimido ester 
OTce 2,2,2-Trichloroethyl ester 
OTcp 2,4,5-Trichlorophenyl ester 
Tmob 2,4,5-Trimethoxybenzyl 
Mtt 4-Methyltrityl 
Pac Phenacyl, PhCOCH2 (care! Pac also=PhCH2CO) 
Ph Phenyl 
Pht Phthaloyl 
Scm Methoxycarbonylsulphenyl 
Pmc 2,2,5,7,8-Pentamethylchroman-6-sulphonyl 
Pri i-Propyl 
Prn n-Propyl 
Tfa Trifluoroacetyl 
Tos 4-Toluenesulphonyl (also Ts) 
Troc 2,2,2-Trichloroethoxycarbonyl 
Trt Trityl, triphenylmethyl 
Xan 9-Xanthydryl 
Benzyloxycarbonyl (also Cbz). Z(2C1)=2-chlorobenzyloxycarbonyl and so on 
Substituents and Protecting Groups
Ac Acetyl 
Acm Acetamidomethyl 
Adoc 1-Adamantyloxycarbonyl 
Alloc Allyloxycarbonyl 
Boc t-Butoxycarbonyl 
Bom π-Benzyloxymethyl 
Bpoc 2-(4-Biphenylyl)isopropoxycarbonyl 
Btm Benzylthiomethyl 
Bum π-t-Butoxymethyl 
Bui i-Butyl 
Bun n-Butyl 
But t-Butyl 
Bz Benzoyl 
Bzl Benzyl (also Bn); Bzl(OMe)=4-methoxybenzyl and so on 
Cha Cyclohexylammonium salt 
Clt 2-Chlorotrityl 
Dcha Dicyclohexylammonium salt 
Dde 1-(4,4-Dimethyl-2,6-dioxocyclohex-1-ylidene)ethyl 
Ddz 2-(3,5-Dimethoxyphenyl)-isopropoxycarbonyl 
Dnp 2,4-Dinitrophenyl 
Dpp Diphenylphosphinyl 
Et Ethyl 
Fmoc 9-Fluorenylmethoxycarbonyl 
For Formyl 
Mbh 4,4′-Dimethoxydiphenylmethyl, 4,4′-Dimethoxybenzhydryl 
Mbs 4-Methoxybenzenesulphonyl 
Me Methyl 
Mob 4-Methoxybenzyl 
Mtr 2,3,6-Trimethyl,4-methoxybenzenesulphonyl 
Nps 2-Nitrophenylsulphenyl 
OA11 Allyl ester 
OBt 1-Benzotriazolyl ester 
OcHx Cyclohexyl ester 
ONp 4-Nitrophenyl ester 
OPcp Pentachlorophenyl ester 
OPfp Pentafluorophenyl ester 
OSu Succinimido ester 
OTce 2,2,2-Trichloroethyl ester 
OTcp 2,4,5-Trichlorophenyl ester 
Tmob 2,4,5-Trimethoxybenzyl 
Mtt 4-Methyltrityl 
Pac Phenacyl, PhCOCH2 (care! Pac also=PhCH2CO) 
Ph Phenyl 
Pht Phthaloyl 
Scm Methoxycarbonylsulphenyl 
Pmc 2,2,5,7,8-Pentamethylchroman-6-sulphonyl 
Pri i-Propyl 
Prn n-Propyl 
Tfa Trifluoroacetyl 
Tos 4-Toluenesulphonyl (also Ts) 
Troc 2,2,2-Trichloroethoxycarbonyl 
Trt Trityl, triphenylmethyl 
Xan 9-Xanthydryl 
Benzyloxycarbonyl (also Cbz). Z(2C1)=2-chlorobenzyloxycarbonyl and so on 
Amino Acid Derivatives
DKP Diketopiperazine 
NCA N-Carboxyanhydride 
PTH Phenylthiohydantoin 
UNCA Urethane N-carboxyanhydride 
Amino Acid Derivatives
DKP Diketopiperazine 
NCA N-Carboxyanhydride 
PTH Phenylthiohydantoin 
UNCA Urethane N-carboxyanhydride 
Reagents and Solvents
BOP 1-Benzotriazolyloxy-tris-dimethylamino-phosphonium hexafluorophosphate 
CDI Carbonyldiimidazole 
DBU Diazabicyclo[5.4.0]-undec-7-ene 
DCCI Dicyclohexylcarbodiimide (also DCC) 
DCHU Dicyclohexylurea (also DCU) 
DCM Dichloromethane 
DEAD Diethyl azodicarboxylate (DMAD=the dimethyl analogue) 
DIPCI Diisopropylcarbodiimide (also DIC) 
DIPEA Diisopropylethylamine (also DIEA) 
DMA Dimethylacetamide 
DMAP 4-Dimethylaminopyridine 
DMF Dimethylformamide 
DMS Dimethylsulphide 
DMSO Dimethylsulphoxide 
DPAA Diphenylphosphoryl azide 
EEDQ 2-Ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline 
HATU 

This is the acronym for the ‘uronium’ coupling reagent derived from HOAt, which was originally thought to have the structure 8, the Hexafluorophosphate salt of the O-(7-Azabenzotriazol-lyl)-Tetramethyl Uronium cation.

graphic

In fact this reagent has the isomeric N-oxide structure 9 in the crystalline state, the unwieldy correct name of which does not conform logically with the acronym, but the acronym continues in use.

graphic

Similarly, the corresponding reagent derived from HOBt has the firmly attached label HBTU (the tetrafluoroborate salt is also used: TBTU), despite the fact that it is not actually a uronium salt.

 
HMP Hexamethylphosphoric triamide (also HMPA, HMPTA) 
HOAt 1-Hydroxy-7-azabenzotriazole 
HOBt 1-Hydroxybenzotriazole 
HOCt 1-Hydroxy-4-ethoxycarbonyl-1,2,3-triazole 
NDMBA N,N′-Dimethylbarbituric acid 
NMM N-Methylmorpholine 
PAM Phenylacetamidomethyl resin 
PEG Polyethylene glycol 
PtBOP 1-Benzotriazolyloxy-tris-pyrrolidinophosphonium hexafluorophosphate 
SDS Sodium dodecyl sulphate 
TBAF Tetrabutylammonium fluoride 
TBTU See remarks under HATU above 
TEA Triethylamine 
TFA Trifluoroacetic acid 
TFE Trifluoroethanol 
TFMSA Trifluoromethanesulphonic acid 
THF Tetrahydrofuran 
WSCI Water soluble carbodiimide: 1-ethyl-3-(3′-dimethylaminopropyl)-carbodiimide hydrochloride (also EDC) 
Reagents and Solvents
BOP 1-Benzotriazolyloxy-tris-dimethylamino-phosphonium hexafluorophosphate 
CDI Carbonyldiimidazole 
DBU Diazabicyclo[5.4.0]-undec-7-ene 
DCCI Dicyclohexylcarbodiimide (also DCC) 
DCHU Dicyclohexylurea (also DCU) 
DCM Dichloromethane 
DEAD Diethyl azodicarboxylate (DMAD=the dimethyl analogue) 
DIPCI Diisopropylcarbodiimide (also DIC) 
DIPEA Diisopropylethylamine (also DIEA) 
DMA Dimethylacetamide 
DMAP 4-Dimethylaminopyridine 
DMF Dimethylformamide 
DMS Dimethylsulphide 
DMSO Dimethylsulphoxide 
DPAA Diphenylphosphoryl azide 
EEDQ 2-Ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline 
HATU 

This is the acronym for the ‘uronium’ coupling reagent derived from HOAt, which was originally thought to have the structure 8, the Hexafluorophosphate salt of the O-(7-Azabenzotriazol-lyl)-Tetramethyl Uronium cation.

graphic

In fact this reagent has the isomeric N-oxide structure 9 in the crystalline state, the unwieldy correct name of which does not conform logically with the acronym, but the acronym continues in use.

graphic

Similarly, the corresponding reagent derived from HOBt has the firmly attached label HBTU (the tetrafluoroborate salt is also used: TBTU), despite the fact that it is not actually a uronium salt.

 
HMP Hexamethylphosphoric triamide (also HMPA, HMPTA) 
HOAt 1-Hydroxy-7-azabenzotriazole 
HOBt 1-Hydroxybenzotriazole 
HOCt 1-Hydroxy-4-ethoxycarbonyl-1,2,3-triazole 
NDMBA N,N′-Dimethylbarbituric acid 
NMM N-Methylmorpholine 
PAM Phenylacetamidomethyl resin 
PEG Polyethylene glycol 
PtBOP 1-Benzotriazolyloxy-tris-pyrrolidinophosphonium hexafluorophosphate 
SDS Sodium dodecyl sulphate 
TBAF Tetrabutylammonium fluoride 
TBTU See remarks under HATU above 
TEA Triethylamine 
TFA Trifluoroacetic acid 
TFE Trifluoroethanol 
TFMSA Trifluoromethanesulphonic acid 
THF Tetrahydrofuran 
WSCI Water soluble carbodiimide: 1-ethyl-3-(3′-dimethylaminopropyl)-carbodiimide hydrochloride (also EDC) 
Techniques
CD Circular dichroism 
COSY Correlated spectroscopy 
CZE Capillary zone electrophoresis 
ELISA Enzyme-linked immunosorbent assay 
ESI Electrospray ionization 
ESR Electron spin resonance 
FAB Fast atom bombardment 
FT Fourier transform 
GLC Gas liquid chromatography 
hplc High performance liquid chromatography 
IR Infra red 
MALDI Matrix-assisted laser desorption ionization 
MS Mass spectrometry 
NMR Nuclear magnetic resonance 
nOe Nuclear Overhauser effect 
NOESY Nuclear Overhauser enhanced spectroscopy 
ORD Optical rotatory dispersion 
PAGE Polyacrylamide gel electrophoresis 
RIA Radioimmunoassay 
ROESY Rotating frame nuclear Overhauser enhanced spectroscopy 
RP Reversed phase 
SPPS Solid phase peptide synthesis 
TLC Thin layer chromatography 
TOCSY Total correlation spectroscopy 
TOF Time of flight 
UV Ultraviolet 
Techniques
CD Circular dichroism 
COSY Correlated spectroscopy 
CZE Capillary zone electrophoresis 
ELISA Enzyme-linked immunosorbent assay 
ESI Electrospray ionization 
ESR Electron spin resonance 
FAB Fast atom bombardment 
FT Fourier transform 
GLC Gas liquid chromatography 
hplc High performance liquid chromatography 
IR Infra red 
MALDI Matrix-assisted laser desorption ionization 
MS Mass spectrometry 
NMR Nuclear magnetic resonance 
nOe Nuclear Overhauser effect 
NOESY Nuclear Overhauser enhanced spectroscopy 
ORD Optical rotatory dispersion 
PAGE Polyacrylamide gel electrophoresis 
RIA Radioimmunoassay 
ROESY Rotating frame nuclear Overhauser enhanced spectroscopy 
RP Reversed phase 
SPPS Solid phase peptide synthesis 
TLC Thin layer chromatography 
TOCSY Total correlation spectroscopy 
TOF Time of flight 
UV Ultraviolet 
Miscellaneous
Ab Antibody 
ACE Angiotensin-converting enzyme 
ACTH Adrenocorticotropic hormone 
Ag Antigen 
AIDS Acquired immunodeficiency syndrome 
ANP Atrial natriuretic polypeptide 
ATP Adenosine triphosphate 
BK Bradykinin 
BSA Bovine serum albumin 
CCK Cholecystokinin 
DNA Deoxyribonucleic acid 
FSH Follicle stimulating hormone 
GH Growth hormone 
HIV Human immunodeficiency virus 
LHRH Luteinizing hormone releasing hormone 
MAP Multiple antigen peptide 
NPY Neuropeptide Y 
OT Oxytocin 
PTH Parathyroid hormone 
QSAR Quantitative structureactivity relationship 
RNA Ribonucleic acid 
TASP Template-assembled synthetic protein 
TRH Thyrotropin releasing hormone 
VIP Vasoactive intestinal peptide 
VP Vasopressin 
  
Miscellaneous
Ab Antibody 
ACE Angiotensin-converting enzyme 
ACTH Adrenocorticotropic hormone 
Ag Antigen 
AIDS Acquired immunodeficiency syndrome 
ANP Atrial natriuretic polypeptide 
ATP Adenosine triphosphate 
BK Bradykinin 
BSA Bovine serum albumin 
CCK Cholecystokinin 
DNA Deoxyribonucleic acid 
FSH Follicle stimulating hormone 
GH Growth hormone 
HIV Human immunodeficiency virus 
LHRH Luteinizing hormone releasing hormone 
MAP Multiple antigen peptide 
NPY Neuropeptide Y 
OT Oxytocin 
PTH Parathyroid hormone 
QSAR Quantitative structureactivity relationship 
RNA Ribonucleic acid 
TASP Template-assembled synthetic protein 
TRH Thyrotropin releasing hormone 
VIP Vasoactive intestinal peptide 
VP Vasopressin 
  

J. H. Jones

Figures & Tables

Proteinogenic Amino Acids 
Ala Alanine 
Arg Arginine 
Asn Asparagine 
Asp Aspartic acid 
Asx Asn or Asp  
Cys Cysteine 
Gln Glutamine 
Glu Glutamic acid 
Glx Gln or Glu  
Gly Glycine 
His Histidine 
Ile Isoleucine 
Leu Leucine 
Lys Lysine 
Met Methionine 
Phe Phenylalanine 
Pro Proline 
Ser Serine 
Thr Threonine 
Trp Tryptophan 
Tyr Tyrosine 
Val Valine 
Proteinogenic Amino Acids 
Ala Alanine 
Arg Arginine 
Asn Asparagine 
Asp Aspartic acid 
Asx Asn or Asp  
Cys Cysteine 
Gln Glutamine 
Glu Glutamic acid 
Glx Gln or Glu  
Gly Glycine 
His Histidine 
Ile Isoleucine 
Leu Leucine 
Lys Lysine 
Met Methionine 
Phe Phenylalanine 
Pro Proline 
Ser Serine 
Thr Threonine 
Trp Tryptophan 
Tyr Tyrosine 
Val Valine 
Aad α-Aminoadipic acid 
βAad β-Aminoadipic acid 
Abu α-Aminobutyric acid 
Aib α-Aminoisobutyric acid; α-methylalanine 
βAla β-Alanine; 3-aminopropionic acid (avoid Bal) 
Asu α-Aminosuberic acid 
Aze Azetidine-2-carboxylic acid 
Cha β-cyclohexylalanine 
Cit Citrulline; 2-amino-5-ureidovaleric acid 
Dha Dehydroalanine (also ΔAla) 
Gla γ-Carboxyglutamic acid 
Glp pyroglutamic acid; 5-oxoproline (also pGlu) 
Hph Homophenylalanine (Hse=homoserine, and so on). Caution is necessary over the use of the prefix homo in relation to α-amino-acid names and the symbols for homo-analogues. When the term first became current, it was applied to analogues in which a side-chain CH2 extension had been introduced. Thus homoserine has a side-chain CH2CH2OH, homoarginine CH2CH2CH2NHC(NH)NH2, and so on. In such cases, the convention is that a new three-letter symbol for the analogue is derived from the parent, by taking H for homo and combining it with the first two characters of the parental symbol hence, Hse, Har and so on. Now, however, there is a considerable literature on β-amino acids which are analogues of α-amino acids in which a CH2 group has been inserted between the α-carbon and carboxyl group. These analogues have also been called homo-analogues, and there are instances for example not only of ‘homophenylalanine', NH2CH(CH2CH2Ph)CO2H, abbreviated Hph, but also ‘homophenylalanine', NH2CH(CH2Ph)CH2CO2H abbreviated Hph.Further, members of the analogue class with CH2 interpolated between the α-carbon and the carboxyl group of the parent α-amino acid structure have been called both ‘α-homo'- and ‘β-homo’. Clearly great care is essential, and abbreviations for ‘homo’ analogues ought to be fully defined on every occasion. The term ‘β-homo’ seems preferable for backbone extension (emphasizing as it does that the residue has become a β-amino acid residue), with abbreviated symbolism as illustrated by βHph for NH2CH(CH2Ph)CH2CO2H. 
Hyl δ-Hydroxylysine 
Hyp 4-Hydroxyproline 
αIle allo-Isoleucine; 2S, 3R in the l-series 
Lan Lanthionine; S-(2-amino-2-carboxyethyl)cysteine 
MeAla N-Methylalanine (MeVal=N-methylvaline, and so on). This style should not be used for α-methyl residues, for which either a separate unique symbol (such as Aib for α-methylalanine) should be used, or the position of the methyl group should be made explicit as in αMeTyr for α-methyltyrosine. 
Nle Norleucine; α-aminocaproic acid 
Orn Ornithine; 2,5-diaminopentanoic acid 
Phg Phenylglycine; 2-aminophenylacetic acid 
Pip Pipecolic acid; piperidine-s-carboxylic acid 
Sar Sarcosine; N-methylglycine 
Sta Statine; (3S, 4S)-4-amino-3-hydroxy-6-methyl-heptanoic acid 
Thi β-Thienylalanine 
Tic 1,2,3,4-Tetrahydroisoquinoline-3-carboxylic acid 
αThr allo-Threonine; 2S, 3S in the l-series 
Thz Thiazolidine-4-carboxylic acid, thiaproline 
Xaa Unknown or unspecified (also Aaa) 
Aad α-Aminoadipic acid 
βAad β-Aminoadipic acid 
Abu α-Aminobutyric acid 
Aib α-Aminoisobutyric acid; α-methylalanine 
βAla β-Alanine; 3-aminopropionic acid (avoid Bal) 
Asu α-Aminosuberic acid 
Aze Azetidine-2-carboxylic acid 
Cha β-cyclohexylalanine 
Cit Citrulline; 2-amino-5-ureidovaleric acid 
Dha Dehydroalanine (also ΔAla) 
Gla γ-Carboxyglutamic acid 
Glp pyroglutamic acid; 5-oxoproline (also pGlu) 
Hph Homophenylalanine (Hse=homoserine, and so on). Caution is necessary over the use of the prefix homo in relation to α-amino-acid names and the symbols for homo-analogues. When the term first became current, it was applied to analogues in which a side-chain CH2 extension had been introduced. Thus homoserine has a side-chain CH2CH2OH, homoarginine CH2CH2CH2NHC(NH)NH2, and so on. In such cases, the convention is that a new three-letter symbol for the analogue is derived from the parent, by taking H for homo and combining it with the first two characters of the parental symbol hence, Hse, Har and so on. Now, however, there is a considerable literature on β-amino acids which are analogues of α-amino acids in which a CH2 group has been inserted between the α-carbon and carboxyl group. These analogues have also been called homo-analogues, and there are instances for example not only of ‘homophenylalanine', NH2CH(CH2CH2Ph)CO2H, abbreviated Hph, but also ‘homophenylalanine', NH2CH(CH2Ph)CH2CO2H abbreviated Hph.Further, members of the analogue class with CH2 interpolated between the α-carbon and the carboxyl group of the parent α-amino acid structure have been called both ‘α-homo'- and ‘β-homo’. Clearly great care is essential, and abbreviations for ‘homo’ analogues ought to be fully defined on every occasion. The term ‘β-homo’ seems preferable for backbone extension (emphasizing as it does that the residue has become a β-amino acid residue), with abbreviated symbolism as illustrated by βHph for NH2CH(CH2Ph)CH2CO2H. 
Hyl δ-Hydroxylysine 
Hyp 4-Hydroxyproline 
αIle allo-Isoleucine; 2S, 3R in the l-series 
Lan Lanthionine; S-(2-amino-2-carboxyethyl)cysteine 
MeAla N-Methylalanine (MeVal=N-methylvaline, and so on). This style should not be used for α-methyl residues, for which either a separate unique symbol (such as Aib for α-methylalanine) should be used, or the position of the methyl group should be made explicit as in αMeTyr for α-methyltyrosine. 
Nle Norleucine; α-aminocaproic acid 
Orn Ornithine; 2,5-diaminopentanoic acid 
Phg Phenylglycine; 2-aminophenylacetic acid 
Pip Pipecolic acid; piperidine-s-carboxylic acid 
Sar Sarcosine; N-methylglycine 
Sta Statine; (3S, 4S)-4-amino-3-hydroxy-6-methyl-heptanoic acid 
Thi β-Thienylalanine 
Tic 1,2,3,4-Tetrahydroisoquinoline-3-carboxylic acid 
αThr allo-Threonine; 2S, 3S in the l-series 
Thz Thiazolidine-4-carboxylic acid, thiaproline 
Xaa Unknown or unspecified (also Aaa) 
Substituents and Protecting Groups
Ac Acetyl 
Acm Acetamidomethyl 
Adoc 1-Adamantyloxycarbonyl 
Alloc Allyloxycarbonyl 
Boc t-Butoxycarbonyl 
Bom π-Benzyloxymethyl 
Bpoc 2-(4-Biphenylyl)isopropoxycarbonyl 
Btm Benzylthiomethyl 
Bum π-t-Butoxymethyl 
Bui i-Butyl 
Bun n-Butyl 
But t-Butyl 
Bz Benzoyl 
Bzl Benzyl (also Bn); Bzl(OMe)=4-methoxybenzyl and so on 
Cha Cyclohexylammonium salt 
Clt 2-Chlorotrityl 
Dcha Dicyclohexylammonium salt 
Dde 1-(4,4-Dimethyl-2,6-dioxocyclohex-1-ylidene)ethyl 
Ddz 2-(3,5-Dimethoxyphenyl)-isopropoxycarbonyl 
Dnp 2,4-Dinitrophenyl 
Dpp Diphenylphosphinyl 
Et Ethyl 
Fmoc 9-Fluorenylmethoxycarbonyl 
For Formyl 
Mbh 4,4′-Dimethoxydiphenylmethyl, 4,4′-Dimethoxybenzhydryl 
Mbs 4-Methoxybenzenesulphonyl 
Me Methyl 
Mob 4-Methoxybenzyl 
Mtr 2,3,6-Trimethyl,4-methoxybenzenesulphonyl 
Nps 2-Nitrophenylsulphenyl 
OA11 Allyl ester 
OBt 1-Benzotriazolyl ester 
OcHx Cyclohexyl ester 
ONp 4-Nitrophenyl ester 
OPcp Pentachlorophenyl ester 
OPfp Pentafluorophenyl ester 
OSu Succinimido ester 
OTce 2,2,2-Trichloroethyl ester 
OTcp 2,4,5-Trichlorophenyl ester 
Tmob 2,4,5-Trimethoxybenzyl 
Mtt 4-Methyltrityl 
Pac Phenacyl, PhCOCH2 (care! Pac also=PhCH2CO) 
Ph Phenyl 
Pht Phthaloyl 
Scm Methoxycarbonylsulphenyl 
Pmc 2,2,5,7,8-Pentamethylchroman-6-sulphonyl 
Pri i-Propyl 
Prn n-Propyl 
Tfa Trifluoroacetyl 
Tos 4-Toluenesulphonyl (also Ts) 
Troc 2,2,2-Trichloroethoxycarbonyl 
Trt Trityl, triphenylmethyl 
Xan 9-Xanthydryl 
Benzyloxycarbonyl (also Cbz). Z(2C1)=2-chlorobenzyloxycarbonyl and so on 
Substituents and Protecting Groups
Ac Acetyl 
Acm Acetamidomethyl 
Adoc 1-Adamantyloxycarbonyl 
Alloc Allyloxycarbonyl 
Boc t-Butoxycarbonyl 
Bom π-Benzyloxymethyl 
Bpoc 2-(4-Biphenylyl)isopropoxycarbonyl 
Btm Benzylthiomethyl 
Bum π-t-Butoxymethyl 
Bui i-Butyl 
Bun n-Butyl 
But t-Butyl 
Bz Benzoyl 
Bzl Benzyl (also Bn); Bzl(OMe)=4-methoxybenzyl and so on 
Cha Cyclohexylammonium salt 
Clt 2-Chlorotrityl 
Dcha Dicyclohexylammonium salt 
Dde 1-(4,4-Dimethyl-2,6-dioxocyclohex-1-ylidene)ethyl 
Ddz 2-(3,5-Dimethoxyphenyl)-isopropoxycarbonyl 
Dnp 2,4-Dinitrophenyl 
Dpp Diphenylphosphinyl 
Et Ethyl 
Fmoc 9-Fluorenylmethoxycarbonyl 
For Formyl 
Mbh 4,4′-Dimethoxydiphenylmethyl, 4,4′-Dimethoxybenzhydryl 
Mbs 4-Methoxybenzenesulphonyl 
Me Methyl 
Mob 4-Methoxybenzyl 
Mtr 2,3,6-Trimethyl,4-methoxybenzenesulphonyl 
Nps 2-Nitrophenylsulphenyl 
OA11 Allyl ester 
OBt 1-Benzotriazolyl ester 
OcHx Cyclohexyl ester 
ONp 4-Nitrophenyl ester 
OPcp Pentachlorophenyl ester 
OPfp Pentafluorophenyl ester 
OSu Succinimido ester 
OTce 2,2,2-Trichloroethyl ester 
OTcp 2,4,5-Trichlorophenyl ester 
Tmob 2,4,5-Trimethoxybenzyl 
Mtt 4-Methyltrityl 
Pac Phenacyl, PhCOCH2 (care! Pac also=PhCH2CO) 
Ph Phenyl 
Pht Phthaloyl 
Scm Methoxycarbonylsulphenyl 
Pmc 2,2,5,7,8-Pentamethylchroman-6-sulphonyl 
Pri i-Propyl 
Prn n-Propyl 
Tfa Trifluoroacetyl 
Tos 4-Toluenesulphonyl (also Ts) 
Troc 2,2,2-Trichloroethoxycarbonyl 
Trt Trityl, triphenylmethyl 
Xan 9-Xanthydryl 
Benzyloxycarbonyl (also Cbz). Z(2C1)=2-chlorobenzyloxycarbonyl and so on 
Amino Acid Derivatives
DKP Diketopiperazine 
NCA N-Carboxyanhydride 
PTH Phenylthiohydantoin 
UNCA Urethane N-carboxyanhydride 
Amino Acid Derivatives
DKP Diketopiperazine 
NCA N-Carboxyanhydride 
PTH Phenylthiohydantoin 
UNCA Urethane N-carboxyanhydride 
Reagents and Solvents
BOP 1-Benzotriazolyloxy-tris-dimethylamino-phosphonium hexafluorophosphate 
CDI Carbonyldiimidazole 
DBU Diazabicyclo[5.4.0]-undec-7-ene 
DCCI Dicyclohexylcarbodiimide (also DCC) 
DCHU Dicyclohexylurea (also DCU) 
DCM Dichloromethane 
DEAD Diethyl azodicarboxylate (DMAD=the dimethyl analogue) 
DIPCI Diisopropylcarbodiimide (also DIC) 
DIPEA Diisopropylethylamine (also DIEA) 
DMA Dimethylacetamide 
DMAP 4-Dimethylaminopyridine 
DMF Dimethylformamide 
DMS Dimethylsulphide 
DMSO Dimethylsulphoxide 
DPAA Diphenylphosphoryl azide 
EEDQ 2-Ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline 
HATU 

This is the acronym for the ‘uronium’ coupling reagent derived from HOAt, which was originally thought to have the structure 8, the Hexafluorophosphate salt of the O-(7-Azabenzotriazol-lyl)-Tetramethyl Uronium cation.

graphic

In fact this reagent has the isomeric N-oxide structure 9 in the crystalline state, the unwieldy correct name of which does not conform logically with the acronym, but the acronym continues in use.

graphic

Similarly, the corresponding reagent derived from HOBt has the firmly attached label HBTU (the tetrafluoroborate salt is also used: TBTU), despite the fact that it is not actually a uronium salt.

 
HMP Hexamethylphosphoric triamide (also HMPA, HMPTA) 
HOAt 1-Hydroxy-7-azabenzotriazole 
HOBt 1-Hydroxybenzotriazole 
HOCt 1-Hydroxy-4-ethoxycarbonyl-1,2,3-triazole 
NDMBA N,N′-Dimethylbarbituric acid 
NMM N-Methylmorpholine 
PAM Phenylacetamidomethyl resin 
PEG Polyethylene glycol 
PtBOP 1-Benzotriazolyloxy-tris-pyrrolidinophosphonium hexafluorophosphate 
SDS Sodium dodecyl sulphate 
TBAF Tetrabutylammonium fluoride 
TBTU See remarks under HATU above 
TEA Triethylamine 
TFA Trifluoroacetic acid 
TFE Trifluoroethanol 
TFMSA Trifluoromethanesulphonic acid 
THF Tetrahydrofuran 
WSCI Water soluble carbodiimide: 1-ethyl-3-(3′-dimethylaminopropyl)-carbodiimide hydrochloride (also EDC) 
Reagents and Solvents
BOP 1-Benzotriazolyloxy-tris-dimethylamino-phosphonium hexafluorophosphate 
CDI Carbonyldiimidazole 
DBU Diazabicyclo[5.4.0]-undec-7-ene 
DCCI Dicyclohexylcarbodiimide (also DCC) 
DCHU Dicyclohexylurea (also DCU) 
DCM Dichloromethane 
DEAD Diethyl azodicarboxylate (DMAD=the dimethyl analogue) 
DIPCI Diisopropylcarbodiimide (also DIC) 
DIPEA Diisopropylethylamine (also DIEA) 
DMA Dimethylacetamide 
DMAP 4-Dimethylaminopyridine 
DMF Dimethylformamide 
DMS Dimethylsulphide 
DMSO Dimethylsulphoxide 
DPAA Diphenylphosphoryl azide 
EEDQ 2-Ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline 
HATU 

This is the acronym for the ‘uronium’ coupling reagent derived from HOAt, which was originally thought to have the structure 8, the Hexafluorophosphate salt of the O-(7-Azabenzotriazol-lyl)-Tetramethyl Uronium cation.

graphic

In fact this reagent has the isomeric N-oxide structure 9 in the crystalline state, the unwieldy correct name of which does not conform logically with the acronym, but the acronym continues in use.

graphic

Similarly, the corresponding reagent derived from HOBt has the firmly attached label HBTU (the tetrafluoroborate salt is also used: TBTU), despite the fact that it is not actually a uronium salt.

 
HMP Hexamethylphosphoric triamide (also HMPA, HMPTA) 
HOAt 1-Hydroxy-7-azabenzotriazole 
HOBt 1-Hydroxybenzotriazole 
HOCt 1-Hydroxy-4-ethoxycarbonyl-1,2,3-triazole 
NDMBA N,N′-Dimethylbarbituric acid 
NMM N-Methylmorpholine 
PAM Phenylacetamidomethyl resin 
PEG Polyethylene glycol 
PtBOP 1-Benzotriazolyloxy-tris-pyrrolidinophosphonium hexafluorophosphate 
SDS Sodium dodecyl sulphate 
TBAF Tetrabutylammonium fluoride 
TBTU See remarks under HATU above 
TEA Triethylamine 
TFA Trifluoroacetic acid 
TFE Trifluoroethanol 
TFMSA Trifluoromethanesulphonic acid 
THF Tetrahydrofuran 
WSCI Water soluble carbodiimide: 1-ethyl-3-(3′-dimethylaminopropyl)-carbodiimide hydrochloride (also EDC) 
Techniques
CD Circular dichroism 
COSY Correlated spectroscopy 
CZE Capillary zone electrophoresis 
ELISA Enzyme-linked immunosorbent assay 
ESI Electrospray ionization 
ESR Electron spin resonance 
FAB Fast atom bombardment 
FT Fourier transform 
GLC Gas liquid chromatography 
hplc High performance liquid chromatography 
IR Infra red 
MALDI Matrix-assisted laser desorption ionization 
MS Mass spectrometry 
NMR Nuclear magnetic resonance 
nOe Nuclear Overhauser effect 
NOESY Nuclear Overhauser enhanced spectroscopy 
ORD Optical rotatory dispersion 
PAGE Polyacrylamide gel electrophoresis 
RIA Radioimmunoassay 
ROESY Rotating frame nuclear Overhauser enhanced spectroscopy 
RP Reversed phase 
SPPS Solid phase peptide synthesis 
TLC Thin layer chromatography 
TOCSY Total correlation spectroscopy 
TOF Time of flight 
UV Ultraviolet 
Techniques
CD Circular dichroism 
COSY Correlated spectroscopy 
CZE Capillary zone electrophoresis 
ELISA Enzyme-linked immunosorbent assay 
ESI Electrospray ionization 
ESR Electron spin resonance 
FAB Fast atom bombardment 
FT Fourier transform 
GLC Gas liquid chromatography 
hplc High performance liquid chromatography 
IR Infra red 
MALDI Matrix-assisted laser desorption ionization 
MS Mass spectrometry 
NMR Nuclear magnetic resonance 
nOe Nuclear Overhauser effect 
NOESY Nuclear Overhauser enhanced spectroscopy 
ORD Optical rotatory dispersion 
PAGE Polyacrylamide gel electrophoresis 
RIA Radioimmunoassay 
ROESY Rotating frame nuclear Overhauser enhanced spectroscopy 
RP Reversed phase 
SPPS Solid phase peptide synthesis 
TLC Thin layer chromatography 
TOCSY Total correlation spectroscopy 
TOF Time of flight 
UV Ultraviolet 
Miscellaneous
Ab Antibody 
ACE Angiotensin-converting enzyme 
ACTH Adrenocorticotropic hormone 
Ag Antigen 
AIDS Acquired immunodeficiency syndrome 
ANP Atrial natriuretic polypeptide 
ATP Adenosine triphosphate 
BK Bradykinin 
BSA Bovine serum albumin 
CCK Cholecystokinin 
DNA Deoxyribonucleic acid 
FSH Follicle stimulating hormone 
GH Growth hormone 
HIV Human immunodeficiency virus 
LHRH Luteinizing hormone releasing hormone 
MAP Multiple antigen peptide 
NPY Neuropeptide Y 
OT Oxytocin 
PTH Parathyroid hormone 
QSAR Quantitative structureactivity relationship 
RNA Ribonucleic acid 
TASP Template-assembled synthetic protein 
TRH Thyrotropin releasing hormone 
VIP Vasoactive intestinal peptide 
VP Vasopressin 
  
Miscellaneous
Ab Antibody 
ACE Angiotensin-converting enzyme 
ACTH Adrenocorticotropic hormone 
Ag Antigen 
AIDS Acquired immunodeficiency syndrome 
ANP Atrial natriuretic polypeptide 
ATP Adenosine triphosphate 
BK Bradykinin 
BSA Bovine serum albumin 
CCK Cholecystokinin 
DNA Deoxyribonucleic acid 
FSH Follicle stimulating hormone 
GH Growth hormone 
HIV Human immunodeficiency virus 
LHRH Luteinizing hormone releasing hormone 
MAP Multiple antigen peptide 
NPY Neuropeptide Y 
OT Oxytocin 
PTH Parathyroid hormone 
QSAR Quantitative structureactivity relationship 
RNA Ribonucleic acid 
TASP Template-assembled synthetic protein 
TRH Thyrotropin releasing hormone 
VIP Vasoactive intestinal peptide 
VP Vasopressin 
  

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References

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