A functional arginine residue in NADPH-dependent aldehyde reductase from pig kidney.
A functional arginine residue in NADPH-dependent aldehyde reductase from pig kidney.
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猪肾 NADPH 依赖性醛还原酶中的功能性精氨酸残基。
DOI：
10.1016/s0021-9258(18)50646-3
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发表时间：
1979
期刊：
影响因子：
--
通讯作者：
T. Flynn
中科院分区：
文献类型：
--
作者：
W. Davidson;T. Flynn
猪肾醛还原酶被2，3-丁二酮、苯乙二醛、甲基乙二醛和1，2-环己二酮灭活。2，3-丁二酮引起酶活性的最快损失，损失速率与2，3-丁二酮的浓度成正比。无论是D-甘油醛，也不是吡啶3-醛，这广泛的具体酶的底物，保护酶的失活，但1 mM NADPH或NADP完全防止活性的损失，由2，3-丁二酮表明参与精氨酸在结合的辅因子。烟酰胺单甘肽（NMN）（还原形式）对失活没有保护作用，而ADP-核糖磷酸提供了完全的保护作用，表明NADPH的后一部分与必需精氨酸相互作用。NMN和ADP-核糖磷酸都是醛还原酶相对于NADPH的竞争性抑制剂。丁二酮修饰的醛还原酶仍然可以结合到蓝色的葡聚糖-琼脂糖4 B柱，表明修饰的精氨酸不结合NADPH。荧光光谱证实了这一点，表明化学修饰的醛还原酶引起了与天然醛还原酶相同的NADPH荧光蓝移。另外感兴趣的是醛还原酶对NADPH荧光的淬灭，除了一个例外，这与所有其他氧化还原酶的荧光行为相反。
Pig kidney aldehyde reductase is inactivated by 2,3-butanedione, phenylglyoxal, methylglyoxal, and 1,2-cyclohexanedione. 2,3-Butanedione caused the most rapid loss in enzyme activity, the rate of loss being proportional to the concentration of 2,3-butanedione. Neither D-glyceraldehyde nor pyridine 3-aldehyde, both substrates for this broadly specific enzyme, protected the enzyme from inactivation but 1 mM NADPH or NADP completely prevented the loss of activity by 2,3-butanedione suggesting the involvement of arginine in the binding of cofactor. Nicotinamide mononucleotide (NMN) (reduced form) offered no protection to inactivation whereas ADP-ribose phosphate gave complete protection indicating that it is the latter portion of NADPH which interacts with the essential arginine. Both NMN and ADP-ribose phosphate are competitive inhibitors of aldehyde reductase with respect to NADPH. Butanedione-modified aldehyde reductase could still bind to a blue dextran-Sepharose 4B column suggesting that the modified arginine did not bind NADPH. This was confirmed by fluorescence spectra which showed that chemically modified aldehyde reductase caused the same blue shift of NADPH fluorescence as did native aldehyde reductase. Of additional interest was the quenching of NADPH fluorescence by aldehyde reductase which, with one exception, is in contrast to the fluorescence behavior of all other oxidoreductases.