Creatine kinase, a histochemical study by the gelatin film-lead precipitation technique

Intracellular compartmentation, structure and function of creatine kinase isoenzymes in tissues with high and fluctuating energy demands: the 'phosphocreatine circuit' for cellular energy homeostasis

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Characterization of transverse tubule membrane proteins: tentative identification of the Mg-ATPase

Vesiculated fragments of chicken skeletal muscle transverse tubule (TT) membranes were analyzed for their content of loosely associated and integral membrane proteins. Of particular interest was the identification of the magnesium-stimulated ATPase (Mg-ATPase), which is characteristically located in native isolated TT vesicles of chicken skeletal muscle [R. A. Sabbadini and V. R. Okamoto (1983) Arch. Biochem. Biophys. 223, 107-119]. A number of the proteins found in vesicular TT preparations were found to be extractable by a mild Triton-X100 treatment and were identified as aldolase, enolase, creatine kinase, glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and pyruvate kinase. Approximately 60% of TT-associated protein was extracted with Triton, resulting in a twofold enrichment of the Mg-ATPase. Concommitantly, one core integral membrane protein possessing a Mr of 102,000 was enriched, suggesting that it is responsible for the Mg-ATPase activity present in chicken skeletal muscle TT membranes.

The role of creatine phosphokinase in supplying energy for the calcium pump system of heart sarcoplasmic reticulum

An investigation of isolated and purified heart sarcoplasmic reticulum performed in the current study indicates the presence of significant creatine phosphokinase (CPK) activity in this preparation. The localization of CPK on the membrane of sarcoplasmic reticulum has been revealed also by an electron microscopic histochemical method. Under the conditions of the Ca(2+)-ATPase reaction in the presence of creatine phosphate, the release of creatine into the reaction medium is observed, the rate of the latter process being dependent on the MgATP concentration in accordance with the kinetic parameters of the Ca2+-ATPase reaction. CPK localized on the reticular membrane is able to maintain the high rate of calcium consumption by the sarcoplasmic reticulum vesicles. The results obtained demonstrate the close functional coupling between CPK and Ca2+-ATPase in the membrane of sarcoplasmic reticulum and indicate the important functional role of CPK in supplying energy for the Ca(2+)-ATPase reaction and ion transport across the membrane of heart sarcoplasmic reticulum.

[Immunohistochemical localization of creatinkinase isoenzymes in human tissue (author's transl)]

The use of an immunohistochemical method permits the localization of creatine kinase isoenzymes MM and BB in tissue sections. Frozen sections are first incubated with the specific antiserum and secondly with the soluble antigen under investigation. The antibody fixed creatine kinase can then be visualized by the tetrazolium-salt linked histochemical reaction. In this way CK-BB was found in the smooth muscle and the mucosa of the human colon. In sections of skeletal muscle CK-MM was predominantly localized in the intermyofibrillar space. Membrane bound activity could be demonstrated in the sarcoplasmic reticulum and the surface membrane after elution of the cytoplasmic enzyme. In the human tonsilla CK-BB was localized in lymphatic and epithelial tissues, CK-MM in the muscle fibers. The isoenzyme patterns in single sections of tonsilla were in parallel determined by the immunotitration assay. The results indicate the usefulness of the combined application of histochemistry and immunotitration in serial tissue sections.

Effect of calcium on creatine kinase activity of cerebellum

The effect of Ca++ ions on the histochemical activity of creatine kinase (CK) was investigated in striated muscle and cerebellum of the rat. The intensity and pattern of CK activity was unchanged in the striated muscle when Ca++ was present in the incubation medium instead of Mg++. In the cerebellum, however, Ca++ inhibited the enzymatic activity except in the Purkinje cells.

Creatine kinase, myokinase, and acetylcholinesterase activities in muscle-forming primary cultures of mouse teratocarcinoma cells

Multipotential mouse teratocarcinoma cells in embryoid bodies were explanted on plastic or collagen substrates. Various modes of cell determination, including myogenesis, occurred. The predominant avenue of differentiation soon became myogenesis: many multinucleated myotubes formed and yielded an extensive network of skeletal muscle fibers. The process does not proceed to normal completion, as the fibers have a paucity of striations and are not contractile. Activities of several enzymes ordinarily associated with muscle differentiation were examined. Acetylcholinesterase activity increases, especially during myotube formation, as in normal myogenesis. However, creatine kinase activity rises during myotube formation and then drops abnormally, and myokinase activity fails to increase appreciably. The fetal isozymic form of creatine kinase is expressed in the cultures, although well differentiated solid tumors taken from mice show attainment of the adult muscle isozyme type if skeletal muscle is demonstrably present. The results are consistent with the interpretation that coordinately regulated changes in gene expressions controlling these functions may be required for later stages of myogenesis.