title: gamma,delta-Dioxovalerate as a substrate for the glyoxalase enzyme system.
abstract: 1. Crude gammadelta-dioxovalerate was synthesized from laevulinate by two different methods and was purified by Sephadex chromatography. Some analytical reactions of the compound are described. 2. gammadelta-Dioxovalerate is a substrate for glyoxalase I and the GSH derivative formed by this enzyme is hydrolysed by glyoxalase II to form d-alpha-hydroxyglutarate. The K(m) of glyoxalase I for gammadelta-dioxovalerate is 1.0x10(-3)m at pH5.8.3. The u.v.-absorption spectrum of thiol ester, synthesized enzymically from gammadelta-dioxovalerate and GSH by glyoxalase I, is almost identical with that for S-lactoylglutathione. Some optical properties of this thiol ester were measured. 4. Attempts to show reversibility of the glyoxalase system reactions with d-alpha-hydroxyglutarate as substrate were unsuccessful. 5. The possible metabolic role of the gammadelta-dioxovalerate reaction is discussed. It is suggested that one of the metabolic functions of the glyoxalase system may be to provide a mechanism for the entry of this compound into the tricarboxylic acid cycle.
mesh_terms: D000447:Aldehydes / Q000378:metabolism*; D055598:Chemical Phenomena; D002621:Chemistry; D002854:Chromatography, Paper; D002952:Citric Acid Cycle; D005978:Glutathione; D006037:Glyoxal; D006863:Hydrogen-Ion Concentration; D007651:Keto Acids / Q000378:metabolism*; D007700:Kinetics; D007982:Levulinic Acids; D008190:Lyases / Q000378:metabolism*; D008956:Models, Chemical; D009904:Optical Rotation; D013329:Structure-Activity Relationship; D013869:Thiolester Hydrolases / Q000378:metabolism*; D014631:Valerates / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D000447:Aldehydes; D007651:Keto Acids; D007982:Levulinic Acids; D014631:Valerates; D006037:Glyoxal; C007509:4,5-dioxovaleric acid; D013869:Thiolester Hydrolases; D008190:Lyases; D005978:Glutathione