Enzymatic production of S-(2-hydroxy-2-carboxyethyl)homocysteine.
The monodeamination product of L-cystathionine, S-(2-oxo-2-carboxyethyl)homocysteine is enzymatically reduced by human and hog L-lactate dehydrogenase to S-(2 hydroxy-2-carboxyhethyl)homocysteine which has been found in the urine of cystathioninuric patients. Km values are 6.6 mM and 13 mM for human and hog enzymes respectively. The reaction is not complete at alkaline pH values because of cyclization of the ketoacid into a 1,4 thiazepine derivative ring. By a coupled enzymatic system of L-amino acid oxidase and L-lactate dehydrogenase S-(2-hydroxy-2-carboxyethyl)homocysteine is also formed from L-cystathionine.
D000818:Animals; D004912:Erythrocytes / Q000201:enzymology; D006710:Homocysteine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000097:blood / Q000378:metabolism*; D009132:Muscles / Q000201:enzymology; D010084:Oxidation-Reduction; D013045:Species Specificity; D013552:Swine
D007202:Indicators and Reagents; D006710:Homocysteine; C048029:S-(2-hydroxy-2-carboxyethyl)homocysteine; D007770:L-Lactate Dehydrogenase