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首页> 外文期刊>Archives of microbiology >PYRUVATE, FERREDOXIN OXIDOREDUCTASE FROM THE SULFATE-REDUCING ARCHAEOGLOBUS FULGIDUS - MOLECULAR COMPOSITION, CATALYTIC PROPERTIES, AND SEQUENCE ALIGNMENTS
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PYRUVATE, FERREDOXIN OXIDOREDUCTASE FROM THE SULFATE-REDUCING ARCHAEOGLOBUS FULGIDUS - MOLECULAR COMPOSITION, CATALYTIC PROPERTIES, AND SEQUENCE ALIGNMENTS

机译：硫酸盐还原古生参中的丙酮酸，铁氧还蛋白氧化还原酶-分子组成，催化性质和序列比对

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Archaeoglobus fulgidus is a hyperthermophilic sulfate-reducing archaeon. In this communication we de scribe the purification and properties of pyruvate:ferredoxin oxidoreductase from this organism. The catabolic enzyme was purified 250-fold to apparent homogeneity with a yield of 16%. The native enzyme had an apparent molecular mass of 120 kDa and was composed of four different subunits of apparent molecular masses of 45, 33, 25, and 13 kDa, indicating an alpha beta gamma delta structure. Per mel, the enzyme contained 0.8 mol thiamine pyrophosphate, 9 mol non-heme iron, and 8 mol acid-labile sulfur. FAD, FMN, lipoic acid, and copper were not found. The purified enzyme showed an apparent K-m for coenzyme A of 0.02 mM, for pyruvate of 0.3 mM, and for clostridial ferredoxin of 0.01 mM, an apparent V-max of 64 U/mg (at 65 degrees C) with a pH optimum near 7.5 and an Arrhenius activation energy of 75 kJ/mol (between 30 and 70 degrees C). The temperature optimum was above 90 degrees C. At 90 degrees C, the enzyme lost 50% activity within 60 min in the presence of 2 M KCl. The enzyme did not catalyze the oxidation of 2-oxoglutarate, indolepyruvate, phenylpyruvate, glyoxylate, and hydroxypyruvate. The N-terminal amino acid sequences of the four subunits were determined. The sequence of the alpha-subunit had similarities to the N-terminal amino acid sequence of the alpha-subunit of the heterotetrameric pyruvate:ferredoxin oxidoreductase from Pyrococcus furiosus and from Thermotoga maritima, and unexpectedly, to the N-terminal amino acid sequence of the homodimeric pyruvate:ferredoxin oxidoreductase from proteobacteria and from cyanobacteria. No sequence similarities were found, however, between the alpha-subunits of the enzyme from A. fulgidus and the heterodimeric pyruvate:ferredoxin oxidoreductase from Halobacterium halobium. [References: 46]
机译：fulgdus古生球菌是一种还原硫酸的超高温古细菌。在本交流中，我们描述了从该生物体中丙酮酸：铁氧还蛋白氧化还原酶的纯化和性质。将分解代谢酶纯化250倍至表观均质，产率为16％。天然酶的表观分子量为120 kDa，由表观分子量为45、33、25和13 kDa的四个不同的亚基组成，表明具有αβγδ结构。对于每蜜，该酶包含0.8 mol硫胺焦磷酸盐，9 mol非血红素铁和8 mol酸不稳定的硫。找不到FAD，FMN，硫辛酸和铜。纯化的酶对辅酶A的表观Km为0.02 mM，对丙酮酸的表观Km为0.3 mM，对于梭菌铁氧还蛋白的表观Km为0.01 mM，表观V-max为64 U / mg（在65摄氏度），最适pH值接近7.5。 Arrhenius活化能为75 kJ / mol（介于30到70摄氏度之间）。最适温度高于90摄氏度。在90摄氏度下，存在2 M KCl的情况下，酶在60分钟内丧失了50％的活性。该酶不催化2-氧戊二酸，吲哚丙酮酸，苯丙酮酸，乙醛酸和羟基丙酮酸的氧化。确定了四个亚基的N-末端氨基酸序列。该α-亚基的序列与来自激烈热球菌和海生热球菌的丙酮酸异四聚体：铁氧还蛋白氧化还原酶的α-亚基的N-末端氨基酸序列相似，并且出乎意料地与该细菌的N-末端氨基酸序列相似。变形杆菌和蓝细菌的同源二聚丙酮酸：铁氧还蛋白氧化还原酶。然而，在来自A.fulgidus的酶的α-亚基和来自Halobacterium halobium的异二聚丙酮酸丙酮酸：铁氧还蛋白氧化还原酶之间未发现序列相似性。 [参考：46]

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