Batie C J, Kamin H
J Biol Chem. 1981 Aug 10;256(15):7756-63.
The interaction between spinach ferredoxin and ferredoxin:NADP+ reductase was studied by varying pH and oxidation-reduction state. The Kd of the oxidized ferredoxin . ferredoxin:NADP+ reductase complex increases with increasing pH in the range from pH 6 to pH 8; the Kd is pH-independent above pH 9. These data are interpreted as showing 1 proton binding/complex at neutral pH. The extent of association of the complex was also varied by manipulation of salt concentration, was also varied by manipulation of salt concentration, and of concentration of the individual proteins. Increased association accompanied a negative shift in potential of ferredoxin relative to that of ferredoxin: NADP+ reductase. Oxidation-reduction titrations showed that the oxidation-reduction potential of ferredoxin is reduced to above -510 mV when in complex with ferredoxin:NADP+ reductase, a change of about -90 mV; the potential of ferredoxin:NADP+ reductase is changed little (no more than +20 mV). Conversely, these data also showed that the oxidation-reduction state of ferredoxin strongly affected its association with the flavoprotein, increasing the Kd at least 30-fold on reduction of ferredoxin.
通过改变pH值和氧化还原状态，研究了菠菜铁氧还蛋白与铁氧还蛋白：NADP +还原酶之间的相互作用。氧化型铁氧还蛋白.铁氧还蛋白：NADP +还原酶复合物的解离常数（Kd）在pH 6至pH 8范围内随pH值升高而增加；在pH 9以上，Kd与pH无关。这些数据被解释为表明在中性pH下有1个质子结合/复合物。复合物的缔合程度也通过改变盐浓度以及单个蛋白质的浓度来改变。铁氧还蛋白相对于铁氧还蛋白：NADP +还原酶的电位负移伴随着缔合增加。氧化还原滴定表明，与铁氧还蛋白：NADP +还原酶复合时，铁氧还蛋白的氧化还原电位降至-510 mV以上，变化约-90 mV；铁氧还蛋白：NADP +还原酶的电位变化很小（不超过+20 mV）。相反，这些数据还表明，铁氧还蛋白的氧化还原状态强烈影响其与黄素蛋白的缔合，铁氧还蛋白还原时Kd增加至少30倍。
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