Metabolism of 2-ketoaldehydes in mold: purification and characterization of glyoxalase I from Aspergillus niger.
Glyoxalase I catalyzing the conversion of methylglyoxal into S-lactoylglutathione in the presence of glutathione was purified approximately 1,400-fold with 2.9% activity yield from mold, Aspergillus niger. The enzyme consisted of a single polypeptide chain with a relative molecular weight of 36,000 on both SDS-polyacrylamide gel electrophoresis and Sephadex G-150 gel filtration. The enzyme was most active at pH 7.0, 35-37 degrees C. Among the various aldehydes tested, the enzyme was active on methylglyoxal and 4,5-dioxovalerate with Km values of 1.25 and 0.87 mM, respectively. The activity of the enzyme was completely inhibited by Zn2+ at 0.5 mM. An equimolar amount of EDTA (0.5 mM) protected the enzyme from inactivation by Zn2+. EDTA competitively (K1 = 1.3 mM) inhibited the activity of the enzyme. Fe2+ was a potent activator for the enzyme, the activation being approximately 2.4-fold at 0.5 mM.
D000447:Aldehydes / Q000378:metabolism*; D001234:Aspergillus niger / Q000201:enzymology*; D002848:Chromatography, DEAE-Cellulose; D004492:Edetic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D007791:Lactoylglutathione Lyase / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D008190:Lyases / Q000378:metabolism*; D008970:Molecular Weight; D011765:Pyruvaldehyde / Q000378:metabolism*; D013379:Substrate Specificity
D000447:Aldehydes; D011765:Pyruvaldehyde; D004492:Edetic Acid; D008190:Lyases; D007791:Lactoylglutathione Lyase