AbstractsBiology & Animal Science

The purification and properties of deoxyadenosine kinase.

by Vivian. Krygier




Institution: McGill University
Department: Department of Biochemistry.
Degree: PhD
Year: 1971
Keywords: Biochemistry.
Record ID: 1489964
Full text PDF: http://digitool.library.mcgill.ca/thesisfile129101.pdf


Abstract

Deoxyadenosine (dAR) kinase, purified about 140 fold from calf thymus, was shown to catalyze the transfer of a phosphate group from specific nucleoside 5'-triphosphate donors to the 5' position of dAR. A purification procedure involving fractionation by streptomycin, protamine sulfate, Sephadex G-150 and DEAE-cellulose was employed. The enzyme required a divalent cation and a phosphate donor for activity. The presence of mercuric ions inhibited the enzyme. The molecular weight of dAR kinase was determined by gel filtration to be about 63,000. ATP, GTP, UTP and dTTP were all capable of serving as phosphate donors. dAR, deoxyguanosine (dGR) and cytidine (CR) but not deoxycytidine were shown to be substrates for the enzyme. The enzyme was subject to inhibition by adenine, guanine, and cytosine deoxynucleoside 5'-mono-, di- and triphosphates as well as by the phosphorylated derivatives of cytosine arabinosine and cytidine. The Km values for dAR, dGRand CR were 7.4 x 10-4 M, 1.1 x 10-3 M and 6.3 x 10-4 M respectively and each was found to competitively inhibit the other. The inhibition produced by dATP, dGTP, dCTP, CTP and araCTP appeared to be competitive with respect to ATP and non competitive with respect to dAR.