@article{kumar_hodgson_1970, title={PARTIAL PURIFICATION AND PROPERTIES OF CHOLINE KINASE FROM COCKROACH, PERIPLANETA-AMERICANA}, volume={33}, DOI={10.1016/0010-406X(70)90484-6}, abstractNote={1. Choline kinase (E.C.2.7.1.32) in the American cockroach, Periplaneta americana, is located in the supernatant fraction obtained by centrifugation at 92,000 g. This enzyme was purified twenty-onefold from the supernatant fraction by ammonium sulfate fractionation and calcium phosphate gel adsorption. 2. The purified enzyme preparation was unstable, losing approximately 40 per cent of its activity in 1 week at −20°C. A divalent cation was required for activity and magnesium was the most effective when compared to calcium, cobalt manganese and nickel. ATP was the only effective phosphate donor when compared to CTP, GTP, ITP and UTP. Excess ATP was inhibitory, the activity curve showing a distinct optimum at 2·5 m-molar ATP. Although an absolute requirement for sulfhydryl groups could not be demonstrated, enzyme activity was greater in the presence of cysteine. 3. Michaelis constants for the purified choline kinase were 6·9 × 10−6 M choline and 5·7 × 10−5 M ethanolamine. No phosphorylation of serine or carnitine was detectable.}, number={1}, journal={COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY}, author={KUMAR, SS and HODGSON, E}, year={1970}, pages={73-&} }