Department of Biological Sciences, The George Washington University, Washington, DC 20052.
Plant Physiol. 1987 Nov;85(3):796-800. doi: 10.1104/pp.85.3.796.
Intact glyoxysomes were isolated from castor bean endosperm on isometric Percoll gradients. The matrix enzyme, malate dehydrogenase, was 80% latent in the intact glyoxysomes. NADH:ferricyanide and NADH:cytochrome c reductase activities were measured in intact and deliberately broken organelles. The latencies of these redox activities were found to be about half the malate dehydrogenase latency. Incubation of intact organelles with trypsin eliminated NADH:cytochrome c reductase activity, but did not affect NADH:ferricyanide reductase activity. NADH oxidase and transhydrogenase activities were negligible in isolated glyoxysomes. Mersalyl and Cibacron blue 3GA were potent inhibitors of NADH:cytochrome c reductase. Quinacrine, Ca(2+) and Mg(2+) stimulated NADH:cytochrome c reductase activity in intact glyoxysomes. The data suggest that some electron donor sites are on the matrix side and some electron acceptor sites are on the cytosolic side of the membrane.
完整的乙醛酸体从巴豆胚乳中通过等密度的 P ercoll 梯度离心分离出来。基质酶苹果酸脱氢酶在完整的乙醛酸体中 80%处于潜伏状态。在完整的和故意破碎的细胞器中测量 NADH：铁氰化物和 NADH：细胞色素 c 还原酶活性。这些氧化还原活性的潜伏时间大约是苹果酸脱氢酶潜伏时间的一半。用胰蛋白酶孵育完整的细胞器会消除 NADH：细胞色素 c 还原酶活性，但不影响 NADH：铁氰化物还原酶活性。NADH 氧化酶和转氢酶活性在分离的乙醛酸体中可以忽略不计。Mersalyl 和 Cibacron blue 3GA 是 NADH：细胞色素 c 还原酶的有效抑制剂。吖啶橙、Ca(2+)和 Mg(2+)刺激完整乙醛酸体中的 NADH：细胞色素 c 还原酶活性。数据表明，一些电子供体位点位于基质侧，一些电子受体位点位于膜的胞质侧。
