Bordetella sp. strain 10d metabolizes 4-amino-3-hydroxybenzoic acid via 2-hydroxymuconic 6-semialdehyde. Cell extracts from 4-amino-3-hydroxybenzoate-grown cells showed high NAD+-dependent 2-hydroxymuconic 6-semialdehyde dehydrogenase, 4-oxalocrotonate tautomerase, 4-oxalocrotonate decarboxylase, and 2-oxopent-4-enoate hydratase activities, but no 2-hydroxymuconic 6-semialdehyde hydrolase activity. These enzymes involved in 4-amino-3-hydroxybenzoate metabolism were purified and characterized. When 2-hydroxymuconic 6-semialdehyde was used as substrate in a reaction mixture containing NAD+ and cell extracts from 4-amino-3-hydroxybenzoate-grown cells, 4-oxalocrotonic acid, 2-oxopent-4-enoic acid, and 4-hydroxy-2-oxovaleric acid were identified as intermediates, and pyruvic acid was identified as the final product. A complete pathway for the metabolism of 4-amino-3-hydroxybenzoic acid in strain 10d is proposed. Strain 10d metabolized 2-hydroxymuconic 6-semialdehyde derived from 4-amino-3-hydroxybenzoic acid via a dehydrogenative route, not via a hydrolytic route. This proposed metabolic pathway differs considerably from the modified meta-cleavage pathway of 2-aminophenol and those previously reported for methyl- and chloro-derivatives.
Bordetella sp. 10d株通过2-羟基穆康酸6-半醛代谢
4-氨基-3-羟基苯甲酸。来自于培养于
4-氨基-3-羟基苯甲酸的细胞的细胞
提取物显示出高
水平的
NAD+-依赖性2-羟基穆康酸6-半
醛脱氢酶、4-草酰克罗通酸
互变异构酶、4-草酰克罗通酸脱羧酶和2-氧戊-4-烯酸
水合酶活性,但没有检测到2-羟基穆康酸6-半醛
水解酶活性。这些参与
4-氨基-3-羟基苯甲酸代谢的酶被纯化并进行了特征分析。当在含有
NAD+和来自于
4-氨基-3-羟基苯甲酸的细胞
提取物的反应混合物中使用2-羟基穆康酸6-半醛作为底物时,4-草酰克罗通酸、2-氧戊-4-烯酸和
4-羟基-2-氧
戊酸被鉴定为中间产物,而
丙酮酸被鉴定为最终产物。提出了10d株对
4-氨基-3-羟基苯甲酸的完整代谢途径。10d株通过脱氢途径代谢由
4-氨基-3-羟基苯甲酸衍生的2-羟基穆康酸6-半醛,而不是通过
水解途径。这种提议的代谢途径与2-
氨基
酚的改良元断裂途径以及之前报道的甲基和
氯衍
生物的途径有显著不同。