Department of Animal Science, University of Connecticut, Storrs, Connecticut 06269-4040, USA.
J Agric Food Chem. 2010 May 12;58(9):5724-9. doi: 10.1021/jf1002842.
Our objective was to determine the combined effects of lactate, LDH, and NAD on metmyoglobin reduction in mitochondria isolated from bovine cardiac muscle. Mitochondria were reacted with various combinations of lactate, LDH, NAD, and mitochondrial inhibitors, and oxygen consumption was measured using a Clark oxygen electrode. Mitochondria (3 mg/mL) and bovine metmyoglobin (0.15 mM) also were reacted with substrates/enzymes/inhibitors to determine mitochondria-mediated metmyoglobin reduction in vitro. Combining lactate-LDH-NAD with isolated mitochondria increased oxygen consumption as well as metmyoglobin reduction compared with those of either control mitochondria (without lactate) or mitochondria with added lactate, at pH 5.6 and 7.4 (p < 0.05). The addition of mitochondrial and LDH inhibitors to lactate-LDH-NAD decreased oxygen consumption and metmyoglobin reduction (p < 0.05). NADH formed from lactate-LDH-NAD can be used for nonenzymatic (via the electron transport chain) and enzymatic (NADH-dependent metmyoglobin reductase) metmyoglobin reduction.
我们的目的是确定乳酸、LDH 和 NAD 对从牛心肌分离的线粒体中还原 metmyoglobin 的联合作用。用不同组合的乳酸、LDH、NAD 和线粒体抑制剂与线粒体反应，并使用克拉克氧电极测量耗氧量。线粒体（3mg/mL）和牛 metmyoglobin（0.15mM）也与底物/酶/抑制剂反应，以确定体外线粒体介导的 metmyoglobin 还原。与 pH5.6 和 7.4 下的对照线粒体（无乳酸）或添加乳酸的线粒体相比，乳酸-LDH-NAD 与分离的线粒体结合可增加耗氧量和 metmyoglobin 还原（p<0.05）。向乳酸-LDH-NAD 中添加线粒体和 LDH 抑制剂可降低耗氧量和 metmyoglobin 还原（p<0.05）。乳酸-LDH-NAD 形成的 NADH 可用于非酶（通过电子传递链）和酶（NADH 依赖性 metmyoglobin 还原酶）metmyoglobin 还原。
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