Homolanthionine synthesis by human liver cystathionase

Abstract Cystathionase of human liver is shown to differ from the rat liver enzyme: it is a more acidic protein, chromatographing on DEAE-cellulose; it is not inhibited by rabbit antirat liver cystathionase serum; the optimum pH for reaction is higher than for the rat enzyme. However, as is the case with the rat, the homolanthionine synthase and homoserine dehydratase activities of human liver are not separated from the cystathionase activity by ammonium sulfate fractionation and starch block electrophoresis.