title: Creatine kinase forms in human skeletal and cardiac muscle.
abstract: The creatine kinase (CK) activity in human skeletal and cardiac muscle submitted to QAE-Sephadex chromatography was found to distribute into three peaks (m and h I, II, III fractions). Characterization according to electrophoretic behaviour, approximate molecular weight, thermal stability and immunological properties unambiguously demonstrated the coincidence of fractions I and III with reference MM-CK and MB-CK isoenzymes, while both cardiac and muscular forms II proved to escape any assignment within the dimeric (M, B) model. A higher molecular weight than for reference CK and the absence of interaction with BB-antiserum resulted for both forms II, which on the contrary were found to diverge as for reactivity to MM-antiserum and stability characteristics. Quantitation of the CK forms, attempted on a limited number of samples, confirmed the expected relative levels of MM-CK and BB-CK and gave evidence for the presence of hII- or mII-CK amounting up to 30% of the total activity in cardiac and skeletal muscle, respectively. The results of the study both confirm a complexity greater than supposed for the CK system and point to the inadequacy of several of the commonly used analytical approaches to derive correct information.
mesh_terms: D002852:Chromatography, Ion Exchange; D003402:Creatine Kinase / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000276:immunology / Q000378:metabolism*; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology*; D009206:Myocardium / Q000201:enzymology*
chemical_list: D007527:Isoenzymes; D003402:Creatine Kinase