Dugan I N, Golovlev E L
Mikrobiologiia. 1982 Mar-Apr;51(2):181-7.
The enzyme apparatus involved in the catabolism of aromatic compounds in rhodococci is characterized by the presence of pyrocatechase and protocatechoate-3,4-dioxygenase as principal enzymes cleaving the aromatic cycle. Metapyrocatechase was found in about 30% of the rhodococci. All the enzymes are inducible. The inductor of pyrocatechase seems to be cyc-cys-muconate, and that of protocatechase appears to be 3-oxoadipate. The metapyrocatechase of rhodococci, in contrast to that of Pseudomonas, is not induced by benzoate, p-toluylate, p-xylene and phenol. The activity of metapyrocatechase rises 20-50 times comparing to the basal level only in the presence of p-cresol. The enzyme has a relatively low activity in rhodococci (50-200 nmole per 1 min per 1 mg of protein), though a very high affinity for methylcatechols. The activity of metapyrocatechase with methylcatechols is 2-5 times as high as that with catechol as a substrate, whereas the activity of pyrocatechase with methylcatechols is two times as low as that with catechol as a substrate. Such additional substrates as acetate, glycerol or fumarate have no effect on the qualitative composition of the key enzymes involved in the degradation of aromatic compounds in Rhodococcus carollinus 172. Glucose represses the synthesis of enzymes cleaving the aromatic ring by 100%. Fumarate taken in a 5-fold excess inhibits the activity of catechol oxygenases by 40%; if it is taken in a 1000-fold excess, it inhibits the enzyme activity by 100%.
红球菌中参与芳香族化合物分解代谢的酶系的特点是，存在焦儿茶酚酶和原儿茶酸-3,4-双加氧酶作为裂解芳香环的主要酶。在约30%的红球菌中发现了间位焦儿茶酚酶。所有这些酶都是可诱导的。焦儿茶酚酶的诱导剂似乎是环-半胱-粘康酸，而原儿茶酸酶的诱导剂似乎是3-氧代己二酸。与假单胞菌不同，红球菌的间位焦儿茶酚酶不受苯甲酸、对甲苯酸、对二甲苯和苯酚的诱导。只有在对甲酚存在的情况下，间位焦儿茶酚酶的活性才比基础水平提高20-50倍。该酶在红球菌中的活性相对较低（每1分钟每1毫克蛋白质50-200纳摩尔），尽管对甲基儿茶酚具有非常高的亲和力。以甲基儿茶酚为底物时，间位焦儿茶酚酶的活性是儿茶酚为底物时的2-5倍，而以甲基儿茶酚为底物时，焦儿茶酚酶的活性比儿茶酚为底物时低两倍。诸如乙酸盐、甘油或富马酸盐之类的额外底物对卡罗利红球菌172中参与芳香族化合物降解的关键酶的定性组成没有影响。葡萄糖可100%抑制裂解芳香环的酶的合成。过量5倍的富马酸盐可抑制儿茶酚氧化酶的活性40%；如果过量1000倍，则可100%抑制酶活性。
