Metabolism and the chemical instability of triose phosphates are sources of cellular cytotoxic α-ketoaldehydes such as methylglyoxal (MG; pyruvaldehyde; 2-oxopropanal).^1–4  Owing to its chemical structure, MG and other α-ketoaldehydes are predictably highly electrophilic and can covalently modify DNA, RNA, and proteins and result in the formation of advanced glycation end-products (AGE) in cells.^5–7  In Escherichia coli, the enzyme MG synthase can convert dihydroxyacetone phosphate (DHAP) into MG.^8–10  It has been proposed that this enzyme in concert with the glyoxalase enzymes, elaborated later in this chapter, produces d-lactate, which upon conversion into pyruvate by the bacterial enzyme d-lactate dehydrogenase, serves as a “glycolytic bypass” that is important under inorganic phosphate limiting growth conditions.¹⁰  Other sources of MG include threonine catabolism and biological oxidation of acetone.^11,12