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Kinetic properties and the functional role of particulate MM‐isoenzyme of creatine phosphokinase bound to heart muscle myofibrils
Author(s) -
Saks V.A.,
Chernousova G.B.,
Vetter R.,
Smirnov V.N.,
Chazov E.I.
Publication year - 1976
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(76)80078-6
Subject(s) - medicine , clinical cardiology , cardiology
Fractional extractions of heart muscle have revealed that about 30% of cellular creatine phosphokinase activity are located in mitochondria and about 20% are bound to myofibrils [ 1,2] . The presence of significant creatine phosphokinase activity in heart and skeletal muscle myofibrils has been demonstrated also in studies of isolated myofibrillar preparations [ 1,3,4] . This particulate enzyme has been found to be electrophoretically identical to MM-isoenzyme of CPK* [l-4] . However, no detailed information concerning its properties including kinetic parameters is available. Comprehensive kinetic analyses have been made only for soluble isoenzymes from skeletal muscle [5-71, brain [.5,8] as well as for the mitochondrial isoenzyme from heart [9,10]. It has been shown recently that creatine phosphokinase isoenzymes may play an active role in intracellular energy transport [2,9,10] . In this situation any information of functional properties of myofibrillar CPK becomes to be of special importance. The purpose of this study was to determine the kinetic parameters of myofibrillar CPK from heart muscle and to compare them with the kinetic parameters of the myofibrillar ATPase reaction and mitochondrial CPK.