Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.4.1 (myosin ATPase)
 1,140 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The localization of creatine kinase M (CK-M) in both normal and acute ischemic canine myocardial cells was studied by immunoelectron microscopy using the anti-CK-M Fab'-horseradish peroxidase conjugate. Myocardial ischemia was induced by occlusion of the left anterior descending coronary artery for 15, 60, or 180 minutes. In the normal myocardial cells, CK-M was localized mostly in the A-band and some in the Z-line, M-line, sarcolemmal membrane, and membrane of sarcoplasmic reticulum. Most CK-M in the A-band appeared to associate with thick fibers. This finding strongly suggests that the CK associated with thick fibers may be the enzyme to rephosphorylate ADP produced by myosin ATPase. In 15 minutes of myocardial ischemia, CK-M showed only minimal changes in its location, i.e., almost similar to normal, indicating that the CK in the A-band still has the ability to couple with myosin ATPase. However, in 60 and 180 minutes of ischemia, the A-band CK dissociated markedly from thick fibers, diffused to the I-band and leaked out to the intercellular spaces. These results suggest that the dissociation and disappearance of the A-band CK from thick fibers induced by progress of myocardial ischemia disrupt the myocardial energy transport system via CK reaction, and lead to the irreversible injury of myocardial cells.
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PMID:[Immunoelectron microscopic studies on the localization of creatine kinase M in normal and ischemic myocardial cells]. 240 81

To clarify the changes in creatine kinase M localization along with the progress of myocardial ischemia, immunoelectron microscopic studies were performed using rabbit anti-canine creatine kinase M Fab'-horseradish peroxidase conjugate in 21 dogs. Myocardial ischemia was induced by occlusion of the left anterior descending coronary artery for 15 (n = 5), 30 (n = 5), 60 (n = 5), or 180 (n = 4) minutes. Two dogs were used as normal controls. As we have already demonstrated, most creatine kinase M in normal myocardial cells was localized over the entire A band in association with the thick filament, suggesting that creatine kinase in this region (A-band creatine kinase) was the enzyme coupled with myosin ATPase. After 15 minutes of ischemia, creatine kinase M showed only minimal changes in its location, indicating that A-band creatine kinase still has the ability to couple with myosin ATPase (reversible injury). However, after 30 minutes of ischemia, A-band creatine kinase diffused markedly to the I band (transitional phase), and after 60 minutes of ischemia, it leaked out to extracellular spaces (irreversible injury). After 180 minutes of ischemia, most A-band creatine kinase disappeared from the myocardial cells (coagulation necrosis). These features of creatine kinase M localization seemed to reflect each stage of ischemic cell injury. We conclude that myocardial ischemia results in a dissociation of creatine kinase molecules from the thick filament, which leads the energy transport system to destruction.
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PMID:Changes in creatine kinase M localization in acute ischemic myocardial cells. Immunoelectron microscopic studies. 840 63