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首页> 外文期刊>Journal of bacteriology >Camphor revisited: involvement of a unique monooxygenase in metabolism of 2-oxo-delta 3-4,5,5-trimethylcyclopentenylacetic acid by Pseudomonas putida.
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Camphor revisited: involvement of a unique monooxygenase in metabolism of 2-oxo-delta 3-4,5,5-trimethylcyclopentenylacetic acid by Pseudomonas putida.

机译：樟脑再访：恶臭假单胞菌参与2-氧代δ3-4,5,5-三甲基环戊烯基乙酸代谢的独特单加氧酶。

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摘要

Previously, Pseudomonas putida was shown to degrade (+)-camphor, and cleavage of the first ring of the bicyclic structure involved two monooxygenases (a hydroxylase and a ring oxygen-inserting enzyme), a dehydrogenase, and spontaneous cleavage of an unstable oxygenation product (lactone). Cleavage of the second ring was not demonstrated but was assumed also to occur by ring oxygen insertion, since the predicted oxygenation product was extracted from whole-cell incubation systems. Our investigation established that metabolism of the first ring cleavage intermediate, 2-oxo-delta 3-4,5,5-trimethylcyclopentenylacetic acid, occurred through the sequential action of two inducible enzymes, a coenzyme A ester synthetase and an oxygenase. The oxygenase was purified to homogeneity and had a molecular weight of 106,000. This enzyme carried a single molecule of flavin adenine dinucleotide and consisted of two identical subunits. Iron was not present at a significant level. The oxygenase was specific for NADPH as the electron donor and absolutely specific for the coenzyme A ester of 2-oxo-delta 3-4,5,5-trimethylcyclopentenylacetic acid as the substrate. The reaction stoichiometry was compatible with this enzyme being a monooxygenase, and a mass spectral analysis of the methyl ester of the product confirmed the insertion of a single oxygen atom. The enzyme appeared to be analogous to, although distinct from. 2,5-diketocamphane 1,2-monooxygenase in catalyzing a "biological Baeyer-Villiger" reaction with the formation of a lactone. Structural analogy suggested that this lactone, like the first, was also unstable and susceptible to spontaneous ring opening, although this was not experimentally established.
机译：以前，恶臭假单胞菌表现出降解（+）-樟脑，双环结构的第一个环的裂解涉及两个单加氧酶（羟化酶和插入环氧的酶），脱氢酶和不稳定氧合产物的自发裂解。 （内酯）。第二个环的裂解未得到证实，但也假定是由于环氧的插入而发生的，因为预测的氧化产物是从全细胞培养系统中提取的。我们的研究确定，第一个环裂解中间体2-氧代-δ3-4,5,5-三甲基环戊烯基乙酸的代谢是通过两种诱导酶，辅酶A酯合成酶和加氧酶的顺序作用而发生的。将加氧酶纯化至均质，分子量为106,000。该酶带有一个黄素腺嘌呤二核苷酸单分子，由两个相同的亚基组成。铁含量不高。加氧酶对于作为电子供体的NADPH是特异的，对于作为底物的2-氧代-δ3-4,5,5-三甲基环戊烯基乙酸的辅酶A酯是绝对特异的。反应化学计量与该酶为单加氧酶相容，并且产物的甲酯的质谱分析证实了单个氧原子的插入。该酶似乎与之相似，尽管不同。 2,5-二酮庚烷1,2-单加氧酶催化“生物拜耶-维利格”反应，形成内酯。结构上的类比表明，这种内酯与第一个一样，也是不稳定的，并且容易自发地开环，尽管这在实验上还没有建立。

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