Human glyoxalase I. cDNA cloning, expression, and sequence similarity to glyoxalase I from Pseudomonas putida

Glyoxalase I (EC 4.4.1.5) catalyzes the transformation of methylglyoxal and glutathione to S-lactoylglutathione. We have isolated human cDNA clones encoding glyoxalase I from a phorbol myristate acetate-treated U937 cDNA library. This cDNA encodes a protein of 184 amino acids with a calculated M(r) of 20,719. The amino acid composition calculated from the deduced amino acid sequence agreed with that reported for glyoxalase I purified from human erythrocytes. The Escherichia coli cells carrying the expression vector of this cDNA acquired methylglyoxal resistance and the cell lysate showed the high activity of glyoxalase I. The amino acid sequence of human glyoxalase I exhibited 57% identity with Pseudomonas putida glyoxalase I at the C-terminal two-thirds, suggesting that the two enzymes may have originated from a common ancestor.