A new rapid assay for measuring deoxycytidylate- and deoxythymidylate-kinase activities

A rapid assay for deoxycytidylate- and deoxythymidylate-kinase has been developed that is applicable also to the assay of other kinase enzymes with minor modifications. The method is based on the ability of a radioactive triphosphate nucleotide to adhere to a DEAE disc under conditions in which the corresponding radioactive monophosphate nucleotide is readily removed. This is accomplished by pretreatment of DE81 paper with dTMP for the assay of thymidylate kinase and subsequent washing with a solution composed of 4 formic acid and 1 m ammonium formate for assay of either enzyme. No pretreatment of DE81 paper is required for assay of dCMP-kinase.