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杜氏盐藻细胞质膜氧化还原系统

陈思学, 李琳, 颜季琼, 焦新之

中科院上海植物生理研究所.上海 200032

摘要

杜氏盐藻细胞质膜具有氧化NAD(P)H、还原Fe(CN)~(3-)_(6)和O_(2)的氧化还原系统。当Fe(CN)~(3-)_(6)浓度为0.6mmol/L时,氧化NADH的K_(m)为96#mu#mol/L,V_(max)为159 nmol 10~(-8)cells min~(-1),最适pH为8.5。Triton X-100可促进NADH和Fe(CN))~(3-)_(6)的氧化还原活性。NDAH能促进藻细胞的氧吸收,最适pH为8.5。在无外源电子供体存在时,细胞质电子提供的电子使Fe(CN))~(3-)_(6)还原。培养液pH影响正常呼吸链、交替氧化酶途径和质膜电子传递链的耗氧比例;当有外源NADH存在时,SHAM明显促进细胞的氧吸收,并且质膜电子传递链的耗氧比例增加。

关键词： 杜氏盐藻; 氧化还原系统; 氧消耗; 呼吸抑制剂

The plasmalemma redox system in unicellular green alga Dunaliella salina

Chen Sixue, Li Lin, Yan Jiqiong, Jiao Xinzhi

Shanghai Institute of Plant Physiology,The Chinese Academy of Sciences.Shanghhai 200032

Abstract

A plasmalemmma (PM)-bound redox system was identified in the unicellular green alga Dunalilla salina,which had the ability to oxidize exogenous NAD (P) H and to reduce Fe(CN)~(3-)_6and O_2.In the presence of Fe(CN)~(3-)_6,NADH was rapidly oxidized with a K_m of 96 #mu#mol/L,a V_max of 159 nmol 10~(-8) cells min~(-1) and an optimum pH of 8.5. Triton X-100 treatment greatly increased the redox activity of the cells in both NADH oxidation and Fe(CN)~(3-)_6 reduction. Exogenous NADH not only increased the activity of Fe(CN)~(3-)_6 reduction,but also stimulated O_2 consumption in a pH range from 5.6 to 9.6,with an optimum pH of 8.5.Without exogenous electron donor, the transmembrane Fe(CN)~(3-)_6 reduction could go on using the electrons from internal electron donors.The medium pH influenced the proportions of O_2 uptake through normal respiration pathway, altenative pathway and PM elecctron transport pathway.In the presence of NADH,SHAM stimulated O_2 uptake greatly,and O_2 consumption through PM electron transport pathway was also increased,especially at alkaline pH.The results suggested that the oxidase in the plasmalemma of D.salina had peroxidase properties and there might be two electron transport pathways.

Key words: Dunaliella salina;Redox system;O_(2) consumption;Respiration inhibitors

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引用本文：

陈思学, 李琳, 颜季琼, 焦新之. 杜氏盐藻细胞质膜氧化还原系统[J]. 生理学报 1996; 48 (2): .

Chen Sixue, Li Lin, Yan Jiqiong, Jiao Xinzhi. The plasmalemma redox system in unicellular green alga Dunaliella salina. Acta Physiol Sin 1996; 48 (2): (in Chinese with English abstract).