Gibson K, Krelhaus W, Harris P
Recent Adv Stud Cardiac Struct Metab. 1975;7:77-83.
Myocardial ornithine decarboxylase appears to have characteristics similar to those of enzymes isolated from other tissues. Ornithine decarboxylase activity decreased very rapidly after the death of the animal. Storage of the cell sap fraction at 0 degrees C or -15 degrees C, however, led to only a small decrease in the enzyme activity up to 3 days after preparation. Pyridoxal phosphate at an optimum of 50 muM was essential for full enzyme activity. Thiol compounds did not increase the myocardial ornithine decarboxylase enzyme activity. The subcellular distribution of the enzyme in the myocardium was found to be different from that reported in other tissues. A partial purification of the enzyme was possible using the proteins precipitated at pH 5 from a cell-soluble fraction or by passing a soluble fraction through a Sephadex G 100 gel column. ATP, ADP, and AMP inhibited ornithine decarboxylase at high concentrations (5 mM), but GTP, CTP, and ITP inhibited at a 1 mM concentration and above.
心肌鸟氨酸脱羧酶似乎具有与从其他组织分离出的酶相似的特性。动物死亡后，鸟氨酸脱羧酶活性迅速下降。然而，在0℃或-15℃下储存细胞液部分，在制备后长达3天内酶活性仅略有下降。最适浓度为50μM的磷酸吡哆醛是酶完全活性所必需的。硫醇化合物不会增加心肌鸟氨酸脱羧酶的活性。发现该酶在心肌中的亚细胞分布与其他组织中报道的不同。使用从细胞可溶部分在pH 5沉淀的蛋白质或通过使可溶部分通过Sephadex G 100凝胶柱，可以对该酶进行部分纯化。ATP、ADP和AMP在高浓度（5 mM）时抑制鸟氨酸脱羧酶，但GTP、CTP和ITP在1 mM及以上浓度时抑制。
