INACTIVATION OF CREATINE-KINASE IS DUE TO THE CONFORMATIONAL-CHANGES OF THE ACTIVE-SITES DURING THERMAL-DENATURATION

The conformational changes of the active site of creatine kinase (ATP: creatine N-phosphotransferase EC 2.7.3.2.) during thermal denaturatio n was followed by changes in fluorescence at the active site of the en zyme labeled by o-phthalaldehyde. Conformational changes of the active site occurred at the same time as inactivation of the enzyme. The act ive site changes occurred before the denaturation of the enzyme molecu le as a whole was detected. The above results showed that the thermal inactivation of the creatine kinase was due to the conformational chan ges of its active sites.