دورية
Changes in phosphorylation of P light chain of myosin in perfused rabbit heart
| العنوان: | Changes in phosphorylation of P light chain of myosin in perfused rabbit heart |
|---|---|
| المؤلفون: | FREARSON, N., SOLARO, R. J., PERRY, S. V. |
| المصدر: | Nature; December 1976, Vol. 264 Issue: 5588 p801-802, 2p |
| مستخلص: | IT is now well established that myosins from vertebrate skeletal and smooth muscles possess a light chain component of 18,000 to 20,000 molecular weight, the P light chain, that can be phosphorylated by an enzyme present in sarcoplasm1–3. This enzyme, myosin light chain kinase, of molecular weight about 77,000 (ref. 4 and E. V. Pires and S.V.P., unpublished) is highly specific for the transfer of the γ phosphate of ATP to a single serine residue1close to the N terminus of the P light chain5. Fully phosphorylated myosin therefore contains 2 mol covalently bound P mol−1as two P light chains are present in each myosin molecule. Dephosphorylation of the P light chain is catalysed by an enzyme, myosin light chain phosphatase, that has recently been characterised6and shown to be highly specific for the P light chain. Myosin light chain phosphatase has a molecular weight of 70,000 and is also present in the sarcoplasm. The presence of such a highly specific enzyme system for the phosphorylation and dephosphorylation of the P light chain strongly suggests a role in the physiological function of muscle. The amounts of the two enzymes present in skeletal muscle are such that it is unlikely that a complete cycle of phosphorylation and dephosphorylation of the P light chain can occur during a single twitch3,7; it could, however, take place within a matter of seconds. We report here that changes in the phosphorylation of the P light chain in the perfused rabbit heart can be correlated with changes in the physiological state of the muscle. |
| قاعدة البيانات: | Supplemental Index |
Full Text Finder | تدمد: | 00280836 14764687 |
|---|---|
| DOI: | 10.1038/264801a0 |