Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activity of a 2.5 S mouse myeloma DNA polymerase (termed DNA polymerase II) measured with either poly(rA) or poly(dA) as template did not require sulfhydryl-reducing reagents, but was sensitive to inhibition by p-hydroxymercuribenzoate and the sulfhydryl-alkylating reagent, N-ethylmaleimide; however, the activity was much more sensitive to inhibition by p-hydroxymercuribenzoate than by the sulfhydryl-alkylating reagent. The p-hydroxymercuribenzoate inhibition appeared to involve the mercurial portion of the p-hydroxymercuribenzoate molecule because HgCl2 was an equally effective inhibitor, while p-hydroxybenzoate had little effect upon enzyme activity. The p-hydroxymercuribenzoate inhibition was reversed by an equal concentration of the sulfhydryl-reducing reagent, dithiothreitol.
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PMID:Differential sensitivity of low molecular weight DNA polymerase to sulfhydryl-blocking reagents. 116 93

An experiment was designed to investigate the reaction mechanism of AP (apurinic or apyrimidinic) DNA endonucleases (APcI, APcII, APcIII) purified from rat liver chromatin. Sulfhydryl compounds (2-mercaptoethanol, dithiothreitol) brought about optimal activities of AP DNA endonucleases and N-ethylmaleimide or HgCl2 inhibited the enzyme activities, indicating the presence of sulfhydryl group at or near the active sites of the enzymes. Mg2+ was essential and 4mM of Mg2+ was sufficient for the optimal activities of AP DNA endonucleases. Km values of APcI, APcII and APcIII for the substrate (E. coli chromosomal AP DNA) were 0.53, 0.27 and 0.36 microM AP sites, respectively. AMP was the most potent inhibitor among adenine nucleotides tested and the inhibition was uncompetitive with respective to the substrate. The Ki values of APcI, APcII and APcIII were 0.35, 0.54 and 0.41mM, respectively. The degree of nick translation of AP DNAs nicked by APcI, APcII and APcIII with Klenow fragment in the presence and absence of T4 polynucleotide kinase or alkaline phosphatase were the same, suggesting that all 3 AP DNA endonucleases excise the phosphodiester bond of AP DNA strand to release 3-hydroxyl nucleotides and 5-phosphomonoester nucleotides.
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PMID:Studies on rat liver nuclear DNA damaged by chemical carcinogen (3'-Me DAB) and AP DNA endonuclease. II. Kinetic properties of AP DNA endonucleases in rat liver chromatin. 171 Sep