Polypeptide domains of ADP-ribosyltransferase obtained by digestion with plasmin.
Proteolysis by plasmin inactivates bovine ADP-ribosyltransferase; therefore, enzymatic activity depends exclusively on the intact enzyme molecule. The transferase was hydrolyzed by plasmin to four major polypeptides, which were characterized by affinity chromatography and N-terminal sequencing. Based on the cDNA sequence for human ADP-ribosyltransferase enzyme [Uchida, K., Morita, T., Sato, T., Ogura, T., Yamashita, R., Noguchi, S., Suzuki, H., Nyunoya, H., Miwa, M., & Sugimura, T. (1987) Biochem. Biophys. Res. Commun. 148, 617-622], a polypeptide map of the bovine enzyme was constructed by superposing the experimentally determined N-terminal sequences of the isolated polypeptides on the human sequence deduced from its cDNA. Two polypeptides, the N-terminal peptide (Mr 29,000) and the polypeptide adjacent to it (Mr 36,000), exhibited binding affinities toward DNA, whereas the C-terminal peptide (Mr 56,000), which accounts for the rest of the transferase protein, bound to the benzamide-Sepharose affinity matrix, indicating that it contains the NAD+-binding site. The fourth polypeptide (Mr 42,000) represents the C-terminal end of the larger C-terminal fragment (Mr 56,000) and was formed by a single enzymatic cut by plasmin of the polypeptide of Mr 56,000. The polypeptide of Mr 42,000 still retained the NAD+-binding site. The plasmin-catalyzed cleavage of the polypeptide of Mr 56,000-42,000 was greatly accelerated by the specific ligand NAD+. Out of a total of 96 amino acid residues sequenced here, there were only 6 conservative replacements between human and bovine ADP-ribosyltransferase.
Buki
K G
KG
Department of Pharmacology, School of Medicine, University of California, San Francisco 94143-0130.
Kun
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D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D005341:Fibrinolysin; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000302:isolation & purification; D011065:Poly(ADP-ribose) Polymerases / Q000302:isolation & purification*; D013045:Species Specificity
D010446:Peptide Fragments; D011065:Poly(ADP-ribose) Polymerases; D005341:Fibrinolysin