Boudreau R J, Drummond G I
J Cyclic Nucleotide Res. 1975;1(4):219-28.
Cyclic nucleotide phosphodiesterase was examined in canine and bovine superior cervical ganglia. Activity in crude supernatant fractions was only slightly stimulated by Ca++ despite the presence of protein activating factor. Three forms of phosphodiesterase were resolved from bovine ganglia supernatant extracts by chromatography on DEAE-cellulose. The first enzyme eluted, (DI), was almost completely specific for cyclic GMP, while the other two (DII and DIII), hydrolyzed both cyclic AMP and cyclic GMP; all were free of heat-stable protein activator. Each enzyme was inhibited by low concentrations of Ca++ in the assay medium. Inhibition by Ca++ was reversed by addition of protein activator, but activity did not increase above the control level. Cyclic AMP hydrolysis by enzyme DII was stimulated by micromolar concentrations of cyclic GMP. This stimulation was reduced by Ca++ unless protein activator was present.
对犬和牛的颈上神经节中的环核苷酸磷酸二酯酶进行了检测。尽管存在蛋白质激活因子，但粗上清液组分中的活性仅受到Ca++的轻微刺激。通过在DEAE-纤维素上进行色谱分析，从牛神经节上清液提取物中分离出三种形式的磷酸二酯酶。第一种洗脱的酶（DI）几乎对环鸟苷酸完全具有特异性，而其他两种（DII和DIII）则水解环腺苷酸和环鸟苷酸；所有这些酶都不含热稳定蛋白激活剂。在测定介质中，每种酶都受到低浓度Ca++的抑制。通过添加蛋白质激活剂可逆转Ca++的抑制作用，但活性不会增加到对照水平以上。微摩尔浓度的环鸟苷酸可刺激酶DII对环腺苷酸的水解。除非存在蛋白质激活剂，否则这种刺激会被Ca++降低。
