Vollmer M D, Fischer P, Knackmuss H J, Schlömann M
Institut für Mikrobiologie, Universität Stuttgart, Germany.
J Bacteriol. 1994 Jul;176(14):4366-75. doi: 10.1128/jb.176.14.4366-4375.1994.
The conversion of 2-chloro-cis,cis-muconate by muconate cycloisomerase from Pseudomonas putida PRS2000 yielded two products which by nuclear magnetic resonance spectroscopy were identified as 2-chloro- and 5-chloromuconolactone. High-pressure liquid chromatography analyses showed the same compounds to be formed also by muconate cycloisomerases from Acinetobacter calcoaceticus ADP1 and Pseudomonas sp. strain B13. During 2-chloro-cis,cis-muconate turnover by the enzyme from P. putida, 2-chloromuconolactone initially was the major product. After prolonged incubation, however, 5-chloromuconolactone dominated in the resulting equilibrium. In contrast to previous assumptions, both chloromuconolactones were found to be stable at physiological pH. Since the chloromuconate cycloisomerases of Pseudomonas sp. strain B13 and Alcaligenes eutrophus JMP134 have been shown previously to produce the trans-dienelactone (trans-4-carboxymethylene-but-2-en-4-olide) from 2-chloro-cis,cis-muconate, they must have evolved the capability to cleave the carbon-chlorine bond during their divergence from normal muconate cycloisomerases.
恶臭假单胞菌PRS2000的粘康酸环异构酶将2-氯-顺,顺-粘康酸转化产生了两种产物，通过核磁共振光谱鉴定为2-氯粘康酸内酯和5-氯粘康酸内酯。高压液相色谱分析表明，乙酸钙不动杆菌ADP1和假单胞菌属菌株B13的粘康酸环异构酶也能形成相同的化合物。在恶臭假单胞菌的酶催化2-氯-顺,顺-粘康酸转化过程中，2-氯粘康酸内酯最初是主要产物。然而，长时间孵育后，5-氯粘康酸内酯在最终的平衡中占主导地位。与之前的假设相反，发现两种氯代粘康酸内酯在生理pH下都是稳定的。由于假单胞菌属菌株B13和嗜碱假单胞菌JMP134的氯代粘康酸环异构酶先前已被证明能从2-氯-顺,顺-粘康酸产生反式二烯内酯（反式-4-羧基亚甲基-2-丁烯-4-醇内酯），它们在从正常的粘康酸环异构酶分化过程中必定进化出了裂解碳-氯键的能力。
