Purification and properties of myosin light-chain kinase from fast skeletal muscle

作者：Euclides Pires, S V Perry · 发表于：Biochemical Journal · 年份：1977 · DOI：10.1042/bj1670137 · 被引用次数：197 · 研究领域：Hemoglobin structure and function、Muscle metabolism and nutrition、Cancer, Hypoxia, and Metabolism

1. A procedure is described for the isolation of myosin light-chain kinase from rabbit fast skeletal muscle as a homogeneous protein. 2. Myosin light-chain kinase is a monomeric enzyme of mol.wt. 77000. Under some conditions of storage it is converted into components of mol.wts. about 50000 and 30000 that possess enzymic activity. 3. The enzyme is clearly different in structure and properties from any other protein kinase so far isolated from muscle. 4. The enzyme is highly specific for the P-light chain (18000-20000-dalton light chain) of myosin and requires Ca2+ for activity. 5. The P-light chain is phosphorylated at a similar rate whether isolated or associated with the rest of the myosin molecule. 6. The effects of pH, bivalent cation and other nucleotides on the enzymic activity are described. 7. The role of the phosphorylation of the P-light chain of myosin in muscle function is discussed.