SULFIDE DEHYDROGENASE FROM THE HYPERTHERMOPHILIC ARCHAEON PYROCOCCUS-FURIOSUS - A NEW MULTIFUNCTIONAL ENZYME INVOLVED IN THE REDUCTION OF ELEMENTAL SULFUR
SULFIDE DEHYDROGENASE FROM THE HYPERTHERMOPHILIC ARCHAEON PYROCOCCUS-FURIOSUS - A NEW MULTIFUNCTIONAL ENZYME INVOLVED IN THE REDUCTION OF ELEMENTAL SULFUR
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DOI：
10.1128/jb.176.21.6509-6517.1994
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发表时间：
1994-11-01
影响因子：
3.2
通讯作者：
ADAMS, MWW
中科院分区：
文献类型：
--
作者：
MA, K;ADAMS, MWW
激烈热球菌是一种厌氧古菌，其通过碳水化合物发酵产生乙酸盐、CO2、酸H-2作为主要产物而在100摄氏度下最佳生长。如果将元素硫（S-0）或多硫化物添加到生长培养基中，则也产生H2S。已显示，负责以铁氧还蛋白作为电子供体产生H1的激烈毕赤酵母的细胞质氢化酶也催化多硫化物还原成H2S（K.马河，巴西-地N.希乔河M. Kelly和M. W. W.亚当斯，美国国家科学院院刊。Acad. Sci. USA 90：5341-5344，1993）。从这种生物体的细胞质中，我们现在已经纯化了一种酶，硫化物脱氢酶（SuDH），它催化多硫化物还原为H2S，NADPH作为电子供体。SuDH是一种异源二聚体，亚基为52，000和29，000 Da。SuDH含有黄素和大约11个铁和6个酸不稳定的硫化物原子/mel，但未检测到其他金属。通过电子顺磁共振光谱分析的酶表明存在四个铁硫中心，其中之一是专门减少NADPH。SuDH在95 ℃下的半衰期约为12小时，在82 ℃下12小时后活性增加50%。该纯酶在80 ℃下以多硫化物（1.2 mM）和NADPH（0.4 mM）作为底物时，具有产生7 μ mol H2S.min（-1）.mg蛋白质（-1）的比活性。表观K-m值分别为1.25 mM和11 μ M。不利用NADH作为多硫化物还原的电子供体。激烈毕赤酵母红氧还蛋白（K-m = 1.6 μ M）也充当SuDH的电子受体，并且SuDH用还原的激烈毕赤酵母铁氧还蛋白（K-m = 0.7 μ M）作为电子供体催化NADP的还原。讨论了SuDH的多种活性及其在SO和多硫化物代谢中的作用。
Pyrococcus furiosus is an anaerobic archaeon that grows optimally at 100 degrees C by the fermentation of carbohydrates yielding acetate, CO2, acid H-2 as the primary products. If elemental sulfur (S-0) or polysulfide is added to the growth medium, H2S is also produced. The cytoplasmic hydrogenase of P. furiosus, which is responsible for H, production with ferredoxin as the electron donor, has been shown to also Catalyze the reduction of polysulfide to H2S (K. Ma, R. N. Schicho, R. M. Kelly, and M. W. W. Adams, Proc. Natl. Acad. Sci. USA 90:5341-5344, 1993). From the cytoplasm of this organism, we have now purified an enzyme, sulfide dehydrogenase (SuDH), which catalyzes the reduction of polysulfide to H2S with NADPH as the electron donor. SuDH is a heterodimer with subunits of 52,000 and 29,000 Da. SuDH contains flavin and approximately 11 iron and 6 acid-labile sulfide atoms per mel, hot no other metals were detected. Analysis of the enzyme by electron paramagnetic resonance spectroscopy indicated the presence of four iron-sulfur centers, one of which was specifically reduced by NADPH. SuDH has a half-life at 95 degrees C of about 12 h and shows a 50% increase in activity after 12 h at 82 degrees C. The pure enzyme has a specific activity of 7 mu mol of H2S produced.min(-1).mg of protein(-1) at 80 degrees C with polysulfide (1.2 mM) and NADPH (0.4 mM) as substrates. The apparent K-m values were 1.25 mM and 11 mu M, respectively. NADH was not utilized as an electron donor for polysulfide reduction. P. furiosus rubredoxin (K-m = 1.6 mu M) also functioned as an electron acceptor for SuDH, and SuDH catalyzed the reduction of NADP with reduced P. furiosus ferredoxin (K-m = 0.7 mu M) as an electron donor. The multiple activities of SuDH and its proposed role in the metabolism of SO and polysulfide are discussed.