由可逆性缺血或氰化钾诱导的肝糖原分解完全由磷酸化酶a催化。

The hepatic glycogenolysis induced by reversible ischaemia or KCN is exclusively catalysed by phosphorylase a.

Vandebroeck A, Uyttenhove K, Bollen M, Stalmans W

Afdeling Biochemie, Faculteit Geneeskunde, Katholieke Universiteit Leuven, Belgium.

Biochem J. 1988 Dec 1;256(2):685-8. doi: 10.1042/bj2560685.

Ischaemia was applied for 30 min to the liver of Wistar rats and of gsd/gsd rats, which have a genetic deficiency of phosphorylase kinase. The rate of glycogenolysis corresponded closely to the concentration of phosphorylase a. The loss of glycogen from Wistar livers was accounted for by the intrahepatic increase in glucose plus lactate. Further, the accumulation of oligosaccharides was negligible in the gsd/gsd liver. 2. Isolated hepatocytes from Wistar and gsd/gsd rats were incubated for 40 min in the presence of either KCN or glucagon. Again, the production of glucose plus lactate was strictly dependent on the presence of phosphorylase a. However, the catalytic efficiency of phosphorylase a was about 2-fold higher in the presence of KCN. 3. We conclude that the hepatic glycogenolysis induced by anoxia and by KCN is solely mediated by phosphorylase a. The higher catalytic activity of phosphorylase a under these circumstances could be due to an increased concentration of the substrate Pi.

对Wistar大鼠和糖原磷酸化酶激酶基因缺陷的gsd/gsd大鼠的肝脏施加30分钟的缺血处理。糖原分解速率与磷酸化酶a的浓度密切相关。Wistar大鼠肝脏中糖原的损失可由肝内葡萄糖和乳酸的增加来解释。此外，在gsd/gsd大鼠肝脏中寡糖的积累可忽略不计。2. 将Wistar大鼠和gsd/gsd大鼠分离的肝细胞在存在KCN或胰高血糖素的情况下孵育40分钟。同样，葡萄糖和乳酸的产生严格依赖于磷酸化酶a的存在。然而，在存在KCN的情况下，磷酸化酶a的催化效率约高2倍。3. 我们得出结论，缺氧和KCN诱导的肝糖原分解仅由磷酸化酶a介导。在这些情况下，磷酸化酶a较高的催化活性可能是由于底物Pi浓度增加所致。

The hepatic glycogenolysis induced by reversible ischaemia or KCN is exclusively catalysed by phosphorylase a.