Partial purification of cyclic nucleotide phosphodiesterase from sheep liver
Al Chalabi K.A.K.
Journal of Biological Sciences Research 18(2): 155-164
Cyclic nucletoide phosphodiesterase activity from sheep liver was purified by fractional precipitation with ammonium sulphate, dialysis and gel filteration on ultrogel-34. Two peaks (I and II) exhibition cyclic nucleotide phosphodiesterase activity were obtained. The optimum conditions of these two forms were determined. Both activities were found to require the addition of Mg+2 ions for full effect; omission of this divalent ion resulted in a loss of activity of about 35%. The apparent Km values for the first and second peaks were 0.13 .times. 10-4 and 0.33 .times. 10-4 M respectively. The enzyme activity was nonspecific for the cyclic nucleotides, and shows different sensitivities to various compounds.