An NAD: Cysteine ADP-Ribosyltransferase Is Present in Human Erythrocytes

抄録

A novel enzymatic activity, i.e., the catalysis of the formation of ADP-ribosylcysteine, was found in the cytosol of human erythrocytes. The NAD: cysteine ADP-ribosyltransferase was partially purified by sequential chromatographic steps on phenylSepharose, phosphocellulose, and Sepharose CL-6B. The enzyme has an apparent molecular weight of 27, 000±3, 000, as determined by gel permeation. The formation of ADP-ribosylcysteine was associated with the stoichiometric release of nicotinamide from NAD. The enzyme was found to be highly specific toward cysteine and cysteine methyl ester as ADP-ribose acceptors. S-Benzoyl-L-cysteine, cystine, histidine, glutamic acid, arginine, arginine methyl ester, and agmatine were ineffective as acceptors for this enzyme.