Bayly R C, Wigmore G J
J Bacteriol. 1973 Mar;113(3):1112-20. doi: 10.1128/jb.113.3.1112-1120.1973.
Mutant strains of Pseudomonas putida strain U have been obtained which are deficient in enzymes of the degradative pathways of phenol and cresols. Mutant strains deficient in catechol 2, 3-oxygenase accumulated the appropriate catechol derivative from cresols. A mutant strain which would not grow on either phenol or a cresol was shown to be deficient in both 2-hydroxymuconic semialdehyde hydrolase and a nicotinamide adenine dinucleotide, oxidized form, (NAD(+))-dependent aldehyde dehydrogenase. When this strain was grown in the presence of phenol or a cresol, the appropriate product of meta fission of these compounds accumulated in the growth medium. A partial revertant of this mutant strain, which was able to grow on ortho- and meta-cresol but not para-cresol, was shown to have regained only the hydrolase activity. This strain was used to show that the products of meta ring fission of the cresols and phenol are metabolized as follows: (i) ortho- and meta-cresol exclusively by a hydrolase; (ii) para-cresol exclusively by a NAD(+)-dependent aldehyde dehydrogenase; (iii) phenol by both a NAD(+)-dependent dehydrogenase and a hydrolase in the approximate ratio of 5 to 1. This conclusion is supported by the substrate specificity and enzymatic activity of the hydrolase and NAD(+)-dependent aldehyde dehydrogenase enzymes of the wild-type strain. The results are discussed in terms of the physiological significance of the pathway. Properties of some of the mutant strains isolated are discussed.
已获得恶臭假单胞菌U菌株的突变株，这些突变株在苯酚和甲酚降解途径的酶方面存在缺陷。缺乏儿茶酚2,3-加氧酶的突变株积累了来自甲酚的相应儿茶酚衍生物。一株在苯酚或甲酚上均不能生长的突变株被证明在2-羟基粘康酸半醛水解酶和烟酰胺腺嘌呤二核苷酸氧化形式（NAD(+)）依赖性醛脱氢酶方面均存在缺陷。当该菌株在苯酚或甲酚存在下生长时，这些化合物间位裂解的相应产物在生长培养基中积累。该突变株的一个部分回复突变体能够在邻甲酚和间甲酚上生长，但不能在对甲酚上生长，结果表明其仅恢复了水解酶活性。该菌株被用于证明甲酚和苯酚间位环裂解产物的代谢方式如下：（i）邻甲酚和间甲酚仅通过水解酶代谢；（ii）对甲酚仅通过NAD(+)依赖性醛脱氢酶代谢；（iii）苯酚通过NAD(+)依赖性脱氢酶和水解酶以约5比1的比例代谢。这一结论得到了野生型菌株水解酶和NAD(+)依赖性醛脱氢酶的底物特异性及酶活性的支持。从该途径的生理意义方面对结果进行了讨论。还讨论了一些分离出的突变株的特性。
