摘要
水稻湘8根细胞质膜制剂具有氧化NADH和还原Fe（CN）的能力。当Fe（CN）浓度为是1mmolL-1时，膜制剂氧化NADH的Km为71μmolL-1，Vmax为435nmol／mg-1proteinmin-1;0．25mmolL－1浓度下，膜制剂还原Fe（CN.）的Km为43，Vmax为476。最适pH均为8．0。抗霉素A，CN－，CCCP对其活性无影响，10μmol·L-1的DCCD和SHAM不同程度地影响其活性。毫摩尔浓度的一价阳离子（Li＋，Na＋，K＋，Rb＋，Cs＋及微摩尔浓度的二价阳离子（Mg2＋，Mn2＋，Ca2＋）对NADH的氧化活性有促进作用。外源NADH和Fe（CN）对根切段的钾吸收具有抑制作用。
Plasma membrane from rice seedling roots isolated by phase partition has the abilities to oxidize NADH and reduce Fe(CN). The redox reactions showed the Mechalis - Menten kinetics for NADH oxidation with a Km of 71μmmol/L-1 and Vmax of 435μmol/mg-1 protein min- 1 respectively, in the presence of 1mmol/L - 1 Fe(CN) and that for Fe(CN) with a Km of 43μmol/L and Vmax of 476nmol/mg- 1 protein min-1 respectively in the presence of 0. 25mmol/L - 1 NADH. For both NADH oxidation and Fe(CN) reduction, the optimum pH is 8. 0. Antimycin A, KCN and CCCP have no influence in the activities of this redox system,but 10μmol/L DCCD and SHAM inhibit the activity of this system to different extent. Univalent cations (Li +, Na+, K +, Rb+, Cs+ ) at the levels of millimolar concentrations, and some divalent cations at micromolar concentrations (Ca2+, Mg2+, Mn2+ ) behaved as stimulators of NADH oxidation activity. External NADH and Fe(CN)3- inhibit the K + uptake of the root segments.
出处
《华东师范大学学报（自然科学版）》
CAS
CSCD
北大核心
1998年第1期92-97,共6页
Journal of East China Normal University(Natural Science)
基金
国家自然科学基金!39470076
