Argyrou Argyrides, Blanchard John S
Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Prog Nucleic Acid Res Mol Biol. 2004;78:89-142. doi: 10.1016/S0079-6603(04)78003-4.
The flavoprotein disulfide reductases represent a family of enzymes that show high sequence and structural homology. They catalyze the pyridine-nucleotide-dependent reduction of a variety of substrates, including disulfide-bonded substrates (lipoamide dehydrogenase, glutathione reductase and functional homologues, thioredoxin reductase, and alkylhydroperoxide reductase), mercuric ion (mercuric ion reductase), hydrogen peroxide (NADH peroxidase), molecular oxygen (NADH oxidase), and the reductive cleavage of a carbonyl-activated carbon-sulfur bond followed by carboxylation (2-ketopropyl-coenzyme-M carboxylase?oxidoreductase). They use at least one nonflavin redox center to transfer electrons from reduced pyridine nucleotide to their substrate through flavin adenine dinucleotide. The nature of the nonflavin redox center located adjacent to the flavin varies and three types have been identified: an enzymic disulfide (most commonly), an enzymic cysteine sulfenic acid (NADH peroxidase and NADH oxidase), and a mixed Cys-S-S-CoA disulfide (coenzyme A disulfide reductase). Selection of the particular nonflavin redox center and utilization of a second, or even a third, nonflavin redox center in some cases presumably represents the most efficient strategy for reduction of the individual substrate.
黄素蛋白二硫化物还原酶是一类具有高度序列和结构同源性的酶。它们催化多种底物的吡啶核苷酸依赖性还原反应，这些底物包括二硫键结合的底物（硫辛酰胺脱氢酶、谷胱甘肽还原酶及其功能同源物、硫氧还蛋白还原酶和烷基过氧化氢还原酶）、汞离子（汞离子还原酶）、过氧化氢（NADH过氧化物酶）、分子氧（NADH氧化酶），以及羰基活化的碳硫键的还原裂解并随后羧化反应（2-酮丙基-辅酶M羧化酶-氧化还原酶）。它们利用至少一个非黄素氧化还原中心，通过黄素腺嘌呤二核苷酸将来自还原型吡啶核苷酸的电子转移到其底物上。位于黄素附近的非黄素氧化还原中心的性质各不相同，已鉴定出三种类型：一种酶促二硫键（最常见）、一种酶促半胱氨酸亚磺酸（NADH过氧化物酶和NADH氧化酶），以及一种混合的半胱氨酸-S-S-辅酶A二硫键（辅酶A二硫化物还原酶）。在某些情况下，选择特定的非黄素氧化还原中心以及利用第二个甚至第三个非黄素氧化还原中心，大概代表了还原单个底物的最有效策略。
