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Molecular Toxicology of Chromatin
Final rept. 1 Jan 1989-31 Dec 1991
SAN FRANCISCO STATE UNIV TIBURON CA TIBURON CENTER FOR ENVIRONMENTAL STUDIES
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The binding of the ADP unlimited ribosyl transferase protein and its polypeptide components, obtained by digestion with plasmin, to histone-Sepharose 4B matrices was determined by a centrifugation technique. Both the intact enzyme protein and the 29 kDa terminal polypeptide bound to histone affinity matrices in a strictly DNA-dependent manner. Whereas the nature of covalently matrix- bound histones had no apparent specificity towards the enzyme protein or its polypeptide components, among the polypeptides only the 29 kDa terminal basic polypeptide associated with the histone affinity matrices in a DNA unlimited dependent manner. The binding properties of spermine-, polylysine- and polyarginine- Sepharose 4B affinity matrices were also determined. The spermine matrix exhibited similarities to the histone affinity matrix, except binding was considerably weaker, whereas affinity matrices of synthetic polyamino acids showed individual variations but did not replace histones as affinity ligands. The catalytic significance of histone-enzyme associations was tested by determining the effects of the polypeptide components on the enzymatic ADP- ribosyl transferase reaction in the presence of a synthetic octadeoxyribonucleotide duplex as coenzyme.
APPROVED FOR PUBLIC RELEASE