Creatine kinase isoenzymes in baboon tissues and organs

We determined the activity of the isoenzymes of creatine kinase in homogenates of fresh tissues from six baboons. Twenty-six tissues were removed from each baboon and the isoenzymes in them were separated by chromatography on diethylaminoethyl-Sephadex A-50. Total activity was greatest in skeletal muscle (2600 U/g wet weight) followed by myocardium (800 U/g), brain (180 U/g), and the bladder and tissues of the gastrointestinal tract (about 100 U/g). Ten tissues had total activities of less than 20 U/g: trachea, lung, kidney, thyroid, gall bladder, liver, spleen, pancreas, common bile duct, and adrenal. Skeletal muscle contained only the MM isoenzyme; myocardium contained 81% MM isoenzyme, 18% MB isoenzyme, and 1% BB isoenzyme. Except for thyroid and pancreas, all other tissues contained mainly the BB isoenzyme. Tissues of the gastrointestinal tract contained significant (7 to 17%) MB isoenzyme activity.