Anaerobic metabolism of L-phenylalanine via benzoyl-CoA in the denitrifying bacterium Thauera aromatica
Anaerobic metabolism of L-phenylalanine via benzoyl-CoA in the denitrifying bacterium Thauera aromatica
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DOI：
10.1007/s002030050504
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发表时间：
1997-10-01
影响因子：
2.8
通讯作者：
Fuchs, G
中科院分区：
文献类型：
--
作者：
Schneider, S;Mohamed, ME;Fuchs, G
在反硝化细菌 Thaueraaromatica（变形菌门 β 亚类的成员）中研究了苯丙氨酸的无氧代谢。苯丙氨酸被完全氧化并被视为细胞碳的唯一来源。有证据表明降解是通过苯甲酰辅酶A作为中心芳香族中间体进行的；在苯丙氨酸上生长的细胞中存在芳香环还原酶苯甲酰辅酶A还原酶。苯丙氨酸氧化成苯甲酰辅酶A的中间体是苯丙酮酸、苯乙醛、苯乙酸、苯乙酰辅酶A和苯乙醛酸。在用苯丙氨酸和硝酸盐生长的细胞提取物中检测到所需的酶。苯丙氨酸氧化成苯甲酰辅酶A由苯丙氨酸转氨酶、苯丙酮酸脱羧酶、苯乙醛脱氢酶(NAD(+))、苯乙酸辅酶A连接酶(AMP-形成)、用硝酸盐将苯乙酰辅酶A氧化成苯乙醛酸的酶和苯乙醛酸：受体催化氧化还原酶。苯丙氨酸氧化成苯乙酸的能力是在苯丙氨酸生长过程中诱导的。有证据表明苯乙酰辅酶A的α-氧化是由膜结合酶催化的。这是关于芳香族氨基酸的完全厌氧降解以及该过程的调控的第一份报告。
The anaerobic metabolism of phenylalanine was studied in the denitrifying bacterium Thauera aromatica, a member of the beta-subclass of the Proteobacteria. Phenylalanine was completely oxidized and sen ed as the sole source of cell carbon. Evidence is presented that degradation proceeds via benzoyl-CoA as the central aromatic intermediate; the aromatic ring-reducing enzyme benzoyl-CoA reductase was present in cells grown on phenylalanine. Intermediates in phenylalanine oxidation to benzoyl-CoA were phenylpyruvate, phenylacetaldehyde, phenylacetate, phenylacetyl-CoA, and phenylglyoxylate. The required enzymes were detected in extracts of cells grown with phenylalanine and nitrate. Oxidation of phenylalanine to benzoyl-CoA was catalyzed by phenylalanine transaminase, phenylpyruvate decarboxylase, phenylacetaldehyde dehydrogenase (NAD(+)), phenylacetate-CoA ligase (AMP-forming), enzyme(s) oxidizing phenylacetyl-CoA to phenylglyoxylate with nitrate, and phenylglyoxylate:acceptor oxidoreductase. The capacity for phenylalanine oxidation to phenylacetate was induced during growth with phenylalanine. Evidence is provided that alpha-oxidation of phenylacetyl-CoA is catalyzed by a membrane-bound enzyme. This is the first report on the complete anaerobic degradation of an aromatic amino acid and the regulation of this process.