Tanaka E, Fukunaga K, Yamamoto H, Iwasa T, Miyamoto E
J Neurochem. 1986 Jul;47(1):254-62. doi: 10.1111/j.1471-4159.1986.tb02857.x.
We have previously isolated two Ca2+, calmodulin-dependent protein kinases with molecular weights of 120,000 (120K enzyme) and 640,000 (640K enzyme), respectively, by gel filtration analysis from rat brain. Chicken gizzard myosin light-chain kinase and the 120K enzyme phosphorylated two light chains of brain myosin, whereas the 640K enzyme phosphorylated both the two light chains and the heavy chain. The phosphopeptides of the light chains digested by Staphylococcus aureus V8 protease were similar among chicken gizzard myosin light-chain kinase, the 120K enzyme, and the 640K enzyme. Only the seryl residue in the light chains and the heavy chain was phosphorylated by the enzymes. The phosphorylation of brain myosin by any of these enzymes led to an increase in actin-activated Mg-ATPase activity. The results suggest that brain myosin is regulated by brain Ca2+, calmodulin-dependent protein kinases in a similar but distinct mechanism in comparison with that of smooth muscle myosin.
我们之前通过凝胶过滤分析从大鼠脑中分离出了两种钙调蛋白依赖性蛋白激酶，分子量分别为120,000（120K酶）和640,000（640K酶）。鸡砂囊肌球蛋白轻链激酶和120K酶使脑肌球蛋白的两条轻链磷酸化，而640K酶使两条轻链和重链都磷酸化。金黄色葡萄球菌V8蛋白酶消化后的轻链磷酸肽在鸡砂囊肌球蛋白轻链激酶、120K酶和640K酶之间相似。这些酶仅使轻链和重链中的丝氨酸残基磷酸化。这些酶中的任何一种对脑肌球蛋白的磷酸化都会导致肌动蛋白激活的Mg-ATP酶活性增加。结果表明，与平滑肌肌球蛋白相比，脑肌球蛋白受脑钙调蛋白依赖性蛋白激酶的调控机制相似但不同。
