Lee A D, Katz A
Exercise and Sports Research Institute, Arizona State University, Tempe 85287.
Biochem J. 1989 Mar 15;258(3):915-8. doi: 10.1042/bj2580915.
Changes in glucose 1,6-bisphosphate and regulators of glucose-1,6-bisphosphate synthase and phosphatase during isometric contraction have been determined. Biopsies were obtained from the quadriceps femoris muscle before and after 20 s of contraction and at fatigue. Glucose 1,6-bisphosphate increased by 35% after 20 s of contraction (P less than 0.001) with no further change at fatigue (P greater than 0.05 versus 20 s). Pi, fructose 1,6-bisphosphate and glycerate 3-phosphate, all inhibitors of the synthase, increased significantly during the first 20 s (P less than 0.05-0.001), whereas muscle pH (decrease in which inhibits synthase) decreased continuously. The decrease in the total adenine nucleotide pool, which is stoichiometric with the increase in IMP (an activator of phosphatase), was not significant after 20 s, but was 15% at fatigue (P less than 0.001). The rapid increase in glucose 1,6-bisphosphate, despite increases in the inhibitors of synthase, suggests that the synthase was activated, possibly by the substrate glycerate 1,3-bisphosphate and/or a yet unknown activator(s). The lack of any further change in glucose 1,6-bisphosphate during the latter part of contraction may be due to concomitant activation of the synthase and phosphatase.
已测定等长收缩过程中1,6 - 二磷酸葡萄糖以及1,6 - 二磷酸葡萄糖合酶和磷酸酶调节因子的变化。在收缩20秒之前、之后以及疲劳时，从股四头肌获取活检样本。收缩20秒后，1,6 - 二磷酸葡萄糖增加了35%（P < 0.001），疲劳时无进一步变化（与收缩20秒相比，P > 0.05）。无机磷酸（Pi）、1,6 - 二磷酸果糖和3 - 磷酸甘油酸，这些合酶的所有抑制剂在最初20秒内显著增加（P < 0.05 - 0.001），而肌肉pH值（其降低会抑制合酶）持续下降。总腺嘌呤核苷酸池的减少与次黄嘌呤核苷酸（IMP，一种磷酸酶激活剂）的增加呈化学计量关系，收缩20秒后不显著，但在疲劳时为15%（P < 0.001）。尽管合酶抑制剂增加，但1,6 - 二磷酸葡萄糖仍迅速增加，这表明合酶可能被底物1,3 - 二磷酸甘油酸和/或一种未知的激活剂激活。收缩后期1,6 - 二磷酸葡萄糖没有任何进一步变化，可能是由于合酶和磷酸酶同时被激活所致。
