CHAPTER 10: Nickel Glyoxalase I

The glyoxalase I and II enzymes partner to employ intracellular thiols to convert metabolically generated α-ketoaldehydes, such as cytotoxic methylglyoxal, into non-toxic d-hydroxyacids. The first enzyme of this detoxification system, glyoxalase I (Glo1), can be divided into two classes according to its metal activation profile. A Zn²⁺-activated class and a Ni²⁺-activated class have been identified. The Ni²⁺-activated Glo1 enzymes have been identified in microorganisms as well as in plants. Structural studies and recent protein engineering initiatives are providing unique insight into the factors contributing to the metal activation profiles of the Glo1 enzymes and, furthermore, are also providing new knowledge on the fundamental relationships between metalloenzyme structure and metal selectivity.