牛瘤胃黏膜、肝脏和脂肪组织中所选糖异生和脂肪生成酶的活性。
Activity of selected gluconeogenic and lipogenic enzymes in bovine rumen mucosa, liver and adipose tissue.
作者信息
Young J W, Thorp S L, De Lumen H Z
出版信息
Biochem J. 1969 Aug;114(1):83-8. doi: 10.1042/bj1140083.
The activities of phosphoenolpyruvate carboxykinase, ;malic enzyme', citrate-cleavage enzyme and glucose 6-phosphate dehydrogenase were assayed in homogenates of rumen mucosa, liver and adipose tissue of cattle. Rumen mucosa cytoplasm contained activities of ;malic enzyme' approximately sevenfold those of phosphoenolpyruvate carboxykinase, suggesting that the conversion of propionate into lactate by rumen mucosa involves ;malic enzyme'. Neither starvation for 8 days nor feeding with a concentrate diet for at least 3 months before slaughter produced enzyme patterns in the tissues different from those in cattle given only hay, except that the all-concentrate diet caused increased activities of glucose 6-phosphate dehydrogenase and ;malic enzyme' in adipose tissues. Rumen mucosa, liver and adipose tissue contained phosphoenolpyruvate carboxykinase activity. ;Malic enzyme' was absent in liver. Citrate-cleavage enzyme activity was present in liver and adipose tissue but was quite low in rumen mucosa. Liver contained much less glucose 6-phosphate dehydrogenase activity than rumen mucosa or adipose tissue.
对牛的瘤胃黏膜、肝脏和脂肪组织匀浆中的磷酸烯醇丙酮酸羧激酶、“苹果酸酶”、柠檬酸裂解酶和葡萄糖6-磷酸脱氢酶的活性进行了测定。瘤胃黏膜细胞质中“苹果酸酶”的活性约为磷酸烯醇丙酮酸羧激酶活性的七倍，这表明瘤胃黏膜将丙酸转化为乳酸的过程涉及“苹果酸酶”。在屠宰前，无论是禁食8天还是用精饲料喂养至少3个月，组织中的酶模式与只喂干草的牛的酶模式没有差异，只是全精饲料日粮使脂肪组织中葡萄糖6-磷酸脱氢酶和“苹果酸酶”的活性增加。瘤胃黏膜、肝脏和脂肪组织中均存在磷酸烯醇丙酮酸羧激酶活性。肝脏中不存在“苹果酸酶”。柠檬酸裂解酶活性存在于肝脏和脂肪组织中，但在瘤胃黏膜中相当低。肝脏中葡萄糖6-磷酸脱氢酶的活性比瘤胃黏膜或脂肪组织低得多。
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