Hopper D J, Kemp P D
J Bacteriol. 1980 Apr;142(1):21-6. doi: 10.1128/jb.142.1.21-26.1980.
Constitutive synthesis of enzymes responsible for methyl group oxidation in 3,5-xylenol degradation and an associated p-cresol methylhydroxylase in Pseudomonas putida NCIB 9869 was shown by their retention at high specific activities in cells transferred from 3,5-xylenol medium to glutamate medium. The specific activities of other enzymes of the 3,5-xylenol pathway declined upon removal of aromatic substrate, consistent with their inducible control. Specific activities of the methyl-oxidizing enzymes showed an eventual decline concomitant with a decrease in the fraction of bacteria capable of growth with 3,5-xylenol; a simultaneous loss of the ability to grow with m-hydroxybenzoate was also observed. The property of 3,5-xylenol utilization could be transferred to another strain of P. putida. It is proposed that enzymes of the 3,5-xylenol pathway and those for conversion of p-cresol to p-hydroxybenzoate are plasmid encoded, that the early methyl-oxidizing enzymes are expressed constitutively, and that the later enzymes are inducible.
恶臭假单胞菌NCIB 9869中负责3,5-二甲苯酚降解的甲基氧化酶和相关的对甲酚甲基羟化酶的组成型合成，通过将细胞从3,5-二甲苯酚培养基转移至谷氨酸培养基后，它们仍保持高比活性得以证明。去除芳香底物后，3,5-二甲苯酚途径中其他酶的比活性下降，这与其诱导型调控一致。甲基氧化酶的比活性最终下降，同时能够利用3,5-二甲苯酚生长的细菌比例也降低；同时还观察到利用间羟基苯甲酸生长的能力丧失。利用3,5-二甲苯酚的特性可以转移到恶臭假单胞菌的另一菌株中。有人提出，3,5-二甲苯酚途径的酶以及将对甲酚转化为对羟基苯甲酸的酶是由质粒编码的，早期的甲基氧化酶是组成型表达的，而后期的酶是诱导型的。
