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玉米根细胞膜铁氰化钾还原酶

陈珈, 王建华

北京农业大学生物学院. 北京(100094)

摘要

玉米根细胞膜制剂具明显的NADH-铁氰化钾还原酶(FCR)活性。铁氰化钾被还原的同时伴有 质子跨膜运输, 反应最适pH为6.5。FCR对NADH和铁氰化钾具有较高的活性反应, 而对NADPH 只有微弱的反应活性。用FCR的潜在活性证实在膜的胞质一侧存在底物结合部位。Mg~(2+)、Mn~(2+)、Ca~(2+)、K~(+)、Na~(+)对酶均有一定的激活 作用, 以Mn~(2+)最强、其次为Mg~(2+)。图5表4参22

关键词： 铁氰化钾还原酶; 细胞膜; 氧化还原系统; 质子跨膜运输; 玉米根

Ferricyanide reductase in plasma membrane of maize roots

Chen Jia, Wang Jianhua

College of Biological Sciences, Beijing Agricultural University. Beijing

Abstract

Marked activity of ferricyanide reductase (FCR), an enzyme catalyzing the reduction of ferricyanide using NADH(or NADPH)as the electron donor, accompanied by transmembrane proton transport has been found in plasma membrane from maize roots. The △#mu#H~(+) formed by transmembrane proton transport in the redox reaction was found to be independent of ATP and not affected by vanadate, an inhibitor of H~(+)-ATPase. The latent activity of FCR showed that the enzyme had more suitable binding site(s) for the substrate on the cytoplasmic side of PM. The K_(m)of FCR for ferricyanide was found to be 70 #mu#mol L~(-1), and its K_(max) 2.1 #mu#mol mg~(-1) protein min~(-1). (with a concentration of NADH of 0.1 mmol L~(-1). The K_(m)for NADH was found to be 42 #mu#molL~(-1) and the K_(max) 1.84#mu#mol mg~(-1) proteim min~(-1)(with a concentration of ferricyanide of 0.25 mmol L~(-1)). The optimum pH of FCR was found to be 6.5. All Kinds of cations (Mg~(2+), Mn~(2+), Ca~(2+), K~(+)and Na~(+))had stimulative effect on ferricyanide reductase reductase activity, which was therefore nonspecific.

Key words: Ferricyanide reductase;Plasma membrane;Oxidation-reduction system;Trans-membrane proton transport;Maize root

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引用本文：

陈珈, 王建华. 玉米根细胞膜铁氰化钾还原酶[J]. 生理学报 1994; 46 (1): .

Chen Jia, Wang Jianhua. Ferricyanide reductase in plasma membrane of maize roots. Acta Physiol Sin 1994; 46 (1): (in Chinese with English abstract).