skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Covalent binding of 4-carbamoylbenzenediazonium chloride to deoxyguanine bases of DNA resulting in apparent irreversible inhibition of Poly(adenosine diphosphoribose) polymerase at the nicotinamide binding site

Journal Article · · Biochemistry; (United States)
DOI:https://doi.org/10.1021/bi00382a023· OSTI ID:5639718

The poly(adenosine diphosphoribose) polymerase activity of isolated liver nuclei was inhibited by 4-carbamoylbenzenediazonium chloride, referred to as 4-diazoniobenzamide, an effect that was dependent on the time of incubation and the concentration of the diazonium compound, with inhibition following first-order kinetics. The inhibition was not reversed by reisolation of nuclie and centrifugal washing, whereas the inhibition by benzamide or 4-aminobenzamide was completely reversible under these conditions. Simultaneous incubation of 4-diazoniobenzamide with benzamide prevented enzyme inhibition. The 4-diazoniobenzoic acid analogue was not inhibitory. The mechanism of action of 4-diazoniobenzamide was traced to a specific covalent binding to (/sup 14/C) dGMP of DNA to form N/sup 2/-((4-carbamoylphenyl)azo)-2'-deoxyguanosine 5'-monophosphate. Coenzymic DNA, by tight association with the polymerase protein, fixes the -C(O)NH/sub 2/ moiety of the adduct at the (/sup 32/P) nicotinamide-binding site of the enzyme.

Research Organization:
Univ. of California, San Francisco
OSTI ID:
5639718
Journal Information:
Biochemistry; (United States), Vol. 26:8
Country of Publication:
United States
Language:
English