Chang G G, Hsu R Y
Biochim Biophys Acta. 1977 Aug 11;483(2):228-35. doi: 10.1016/0005-2744(77)90051-1.
Incubation of malic enzyme (L-malate:NADP+ oxidoreductase (oxaloacetate-decarboxylating), EC 1.1.1.40) with ethoxyformic anhydride caused the time-dependent loss of its ability to catalyze reactions requiring the nucleotide cofactor NADP+ or NADPH, such as the oxidative decarboxylase, the NADP+ - stimualted oxalacetate decarboxylase, the pyruvate reductase, and the pyruvate-medium proton exchange activities. Similar loss of oxidative decarboxylase and pyruvate reductase activities was affected by photo-oxidation in the presence of rose bengal. The inactivation of oxidative decarboxylase activity by ethoxyformic anhydride was accompanied by the reaction of greater than or equal to 2.3 histidyl residues per enzyme site and was strongly inhibited by NADP+. Ethoxyformylation also impaired the ability of malic enzyme to bind NADP+ or NADPH. These results support the involvement of histidyl residue(s) at the nucleotide binding site of malic enzyme.
苹果酸酶（L-苹果酸：NADP⁺氧化还原酶（草酰乙酸脱羧），EC 1.1.1.40）与乙氧甲酰酐温育会导致其催化需要核苷酸辅因子NADP⁺或NADPH的反应的能力随时间丧失，例如氧化脱羧酶、NADP⁺刺激的草酰乙酸脱羧酶、丙酮酸还原酶以及丙酮酸-介质质子交换活性。在孟加拉玫瑰红存在下的光氧化也会导致氧化脱羧酶和丙酮酸还原酶活性出现类似丧失。乙氧甲酰酐使氧化脱羧酶活性失活的同时，每个酶位点会有大于或等于2.3个组氨酸残基发生反应，并且受到NADP⁺的强烈抑制。乙氧甲酰化还损害了苹果酸酶结合NADP⁺或NADPH的能力。这些结果支持了组氨酸残基参与苹果酸酶核苷酸结合位点的作用。
