Departments of Microbiology and Health Services Administration and Community Medicine, University of Alberta, Edmonton, Alberta, Canada T6G 2E9.
Appl Environ Microbiol. 1990 Feb;56(2):472-8. doi: 10.1128/aem.56.2.472-478.1990.
The metabolism of m-cresol by methanogenic cultures enriched from domestic sewage sludge was investigated. In the initial studies, bromoethanesulfonic acid was used to inhibit methane production. This led to the accumulation of 4.0 +/- 0.8 mol of acetate per mol of m-cresol metabolized. These results suggested that CO(2) incorporation occurred because each molecule of m-cresol contained seven carbon atoms, whereas four molecules of acetate product contained a total of eight carbon atoms. To verify this, [C]bicarbonate was added to bromoethanesulfonic acid-inhibited cultures, and those cultures yielded [C]acetate. Of the label recovered as acetate, 89% was found in the carboxyl position. Similar cultures fed [methyl-C]m-cresol yielded methyl-labeled acetate. A C-labeled transient intermediate was detected in cultures given either m-cresol and [C]bicarbonate or bicarbonate and [methyl-C]m-cresol. The intermediate was identified as 4-hydroxy-2-methylbenzoic acid. In addition, another metabolite was detected and identified as 2-methylbenzoic acid. This compound appeared to be produced only sporadically, and it accumulated in the medium, suggesting that the dehydroxylation of 4-hydroxy-2-methylbenzoic acid led to an apparent dead-end product.
研究了从生活污水污泥中富集的产甲烷菌培养物对间甲酚的代谢。在最初的研究中，使用溴乙磺酸钠来抑制甲烷生成。这导致每摩尔间甲酚代谢物积累 4.0 +/- 0.8 摩尔的乙酸。这些结果表明发生了 CO(2)掺入，因为每个间甲酚分子含有七个碳原子，而四个乙酸产物分子总共含有八个碳原子。为了验证这一点，向溴乙磺酸钠抑制的培养物中添加 [C]碳酸氢盐，这些培养物产生 [C]乙酸盐。作为乙酸回收的标记，89%存在于羧基位置。用 [甲基-C]间甲酚喂养类似的培养物，得到甲基标记的乙酸盐。在给予间甲酚和 [C]碳酸氢盐或碳酸氢盐和 [甲基-C]间甲酚的培养物中检测到 C 标记的瞬态中间产物。该中间产物被鉴定为 4-羟基-2-甲基苯甲酸。此外，还检测到并鉴定出另一种代谢产物为 2-甲基苯甲酸。这种化合物似乎只是偶尔产生，并且在培养基中积累，表明 4-羟基-2-甲基苯甲酸的脱羟基化导致了明显的死端产物。
