Abstract

Turkey erythrocytes contain NAD:arginine mono-ADP-ribosyltransferases which, like cholera toxin and Escherichia coli heat-labile enterotoxin, catalyze the transfer of ADP-ribose from NAD to proteins, to arginine and other low molecular weight guanidino compounds, and to water. Two such ADP-ribosyltransferases, A and B, have been purified from turkey erythrocyte cytosol. To characterize further the class of NAD:arginine ADP-ribosyltransferases, the particulate fraction was examined; 40% of erythrocyte transferase activity was localized to the nucleus and cell membrane. Transferase activity in a salt extract of a thoroughly washed particulate preparation was purified 36,000-fold by sequential chromatography on phenyl-Sepharose, (carboxymethyl) cellulose, concanavalin A-Sepharose, and NAD-agarose. Subsequent DNA-agarose chromatography separated two activities, termed transferases C and A', which were localized to the membrane and nucleus, respectively. Transferase C, the membrane-associated enzyme, was distinguished from the cytosolic enzymes by a relative insensitivity to salt and histone; transferase C was stimulated 2-fold by 300 mM NaCl in contrast to a 20-fold stimulation of transferase A and a 50% inhibition of transferase B. Similarly, histones, which stimulate transferase A 20-fold, enhanced transferase C activity only 2-fold. Transferase A', the nuclear enzyme, was retained on DNA-agarose. It was similar to transferase A in salt and histone sensitivity. Gel permeation chromatography showed slight molecular mass differences among the group of enzymes: A, 24,300 daltons (Da); B, 32,700 Da; C, and A', 25,500 Da. The affinities of transferase C for NAD and agmatine were similar to those of the cytosolic transferases A and B.(ABSTRACT TRUNCATED AT 250 WORDS)

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