肌酸激酶在低浓度脲溶液中失活也非二聚体解聚所致

INACTIVATION OF GREATINE KINASE AT LOW UREA CONCENTRATIONS IS NOT DUE TO THE DISSOCIATION OF THE DIMERIC ENZYME

本文用兔肌肌酸激酶(MM)和兔脑肌酸激酶(BB)杂化的方法;研究了肌酸激酶在脲溶液中的解聚情况.结果表明在低浓度的脲溶液中二聚体没有或者很少解聚,而此时酶已经失去大部分或全部活性.因此可以认为在低浓度脲溶液中酶的失活也非二聚体解聚所致,进一步支持了酶分子活性部位柔性的观点.

Dissociation of dimeric creatine kinases in urea solutions of different concentrations was studied by hybridization of the muscle and brain enzymes (MM and BB) from rabbit It has been found that the enzyme has been mostly inactivated in low urea concentrations, it is still in the dimeric state or only very little was dissociated. It appears therefor that in low urea concentrations, inactivation of creatine kinase is not due to the dissociation of the active dimer. The present result supports that the conformational state of the active site of this enzyme is very fragile and easily disrupted.