Abstract
A simple method for the amay of adenyl cyclase in tissue homogenates is described that uses either α-P82-, C14-or H3-labeled adenosine triphosphate (ATP) as substrate. Cyclic 3’, 5’- adenosine monophosphate (cyclic 3’, S’-AMP) formed during the incubation was isolated by chromatography on Dowex 50-H+ columns followed by precipitation of all nucleotides and inorganic phosphates by ZnSO4-Ba(OH)2, treatment, which left cyclic 3’, S’-AMP in the supernatant fluid. The purity of the cyclic 3’, 5’-AMP fraction was determined with the use of ion-exchange chromatography and paper chromatographic and electrophoretic techniques, as well as crystallization to constant specific activity. Furthermore, the purity of the nucleotide has been assessed enzymatically, by utilizing a purified cyclic nucleotide phosphodiesterase. The method described here makes possible the measurement of enzyme activities in tissue weighing less than 1 mg. Moreover, the entire procedure can be completed less than 3 hr.
Footnotes
- Received March 25, 1968.
- Accepted May 28, 1968.
- © 1968 by the Williams & Wilkins Co.
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