Interaction of calmodulin with skeletal muscle myosin light chain kinase
| Autor: | John H. Collins, James D. Potter, R. John Solaro, M J Holroyde, Thomas H. Crouch |
|---|---|
| Rok vydání: | 1981 |
| Předmět: |
Myosin light-chain kinase
Meromyosin Calmodulin biology Protein Conformation Chemistry Muscles Calcium-Binding Proteins Skeletal muscle Biochemistry Tropomyosin Molecular Weight Kinetics Enzyme activator medicine.anatomical_structure Myosin Biophysics biology.protein medicine Animals Rabbits Myosin-Light-Chain Kinase Protein Kinases Stokes radius |
| Zdroj: | Biochemistry. 20:6318-6325 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi00525a006 |
| Popis: | Studies on myosin light chain kinase isolated from rabbit skeletal muscle show that the enzyme has a molecular weight of 80,000--84,000 with a sedimentation coefficient of 3.2 S and an apparent Stokes radius of 53 A. Gel filtration chromatography with a 3H-labeled calmodulin using a Hummel--Dryer technique shows that the enzyme will bind 1 mol of calmodulin per mol of enzyme, with an affinity of (1.9 +/- 0.5) x 10(7) M-1 in the absence of substrate. The calmodulin dependence of enzyme activation at limiting Mg2+ and light chain concentrations confirms this observation. The calcium dependence of activation of the enzyme--calmodulin complex is characterized by a Hill coefficient of 2.5, with half-activation occurring at 6.6 x 10(-7) M Ca2+. The amino acid composition shows a high percentage (9.1%) of proline, which may account for the large apparent Stokes radius and no clear resemblance to other skeletal muscle proteins. A comparison of the amino acid composition with that from turkey gizzard shows some resemblance. |
| Databáze: | OpenAIRE |
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