Nakamoto H, Edwards G E
Department of Botany, Washington State University, Pullman, Washington 99164-4230.
Plant Physiol. 1986 Sep;82(1):312-5. doi: 10.1104/pp.82.1.312.
Pyruvate,Pi dikinase (PPDK, EC 2.7.9.1) and NADP-malate dehydrogenase (MDH, EC 1.1.1.82) were activated in the light and inactivated following a dark treatment in mesophyll protoplasts of maize. DCMU (up to 33 micromolar), an inhibitor of noncyclic electron transport, inhibited activation of MDH much more strongly than it did PPDK. Antimycin A (6.6-33 micromolar), an inhibitor of cyclic photophosphorylation, inhibited the activation of PPDK (up to 61%), but had little or no effect on activation of MDH. Carbonyl cyanide m-chlorophenylhydrazone (0.2-2 micromolar) and nigericin (0.4 micromolar), uncouplers of photophosphorylation, inhibited activation of PPDK while stimulating the activation of MDH. Phlorizin (0.33-1.7 millimolar), an inhibitor of the coupling factor for ATP synthesis, strongly inhibited activation of PPDK but only slightly effected light activation of MDH. These results suggest that noncyclic electron flow is required for activation of NADP-MDH and that photophosphorylation is required for activation of PPDK.
丙酮酸、磷酸二激酶（PPDK，EC 2.7.9.1）和NADP - 苹果酸脱氢酶（MDH，EC 1.1.1.82）在玉米叶肉原生质体中光照下被激活，黑暗处理后失活。DCMU（高达33微摩尔），一种非循环电子传递抑制剂，对MDH激活的抑制作用比对PPDK的抑制作用强得多。抗霉素A（6.6 - 33微摩尔），一种循环光合磷酸化抑制剂，抑制PPDK的激活（高达61%），但对MDH的激活几乎没有影响。羰基氰化物间氯苯腙（0.2 - 2微摩尔）和尼日利亚菌素（0.4微摩尔），光合磷酸化解偶联剂，抑制PPDK的激活，同时刺激MDH的激活。根皮苷（0.33 - 1.7毫摩尔），一种ATP合成偶联因子的抑制剂，强烈抑制PPDK的激活，但对MDH的光激活只有轻微影响。这些结果表明，NADP - MDH的激活需要非循环电子流，而PPDK的激活需要光合磷酸化。
