Udaltsov S N, Stepkowski D, Freydina N A, Podlubnaya Z A
Institute of Theoretical and Experimental Biophysics, USSR Academy of Sciences, Pushchino, Moscow.
Biochem Int. 1991 Dec;25(5):837-43.
The effects of C-protein on actin-activated myosin ATPase depending on Ca(2+)-level and LC2-phosphorylation were studied. Column-purified myosin and non-regulated actin were used. At ionic strength of 0.06 C-protein inhibits actomyosin ATPase activity both in the presence and in the absence of calcium, more effective in the case of dephosphorylated myosin. For this myosin, at mu = 0.12 C-protein activates actomyosin ATPase at pCa4, but slightly inhibits at pCa8. No such effects have been observed in the case of phosphorylated myosin. The possibility of coordinative action of LC2-chains and C-protein in regulatory mechanism of skeletal muscle contraction is discussed.
研究了C蛋白对肌动蛋白激活的肌球蛋白ATP酶的影响，该影响取决于钙离子水平和轻链2（LC2）磷酸化。使用了柱纯化的肌球蛋白和非调节性肌动蛋白。在离子强度为0.06时，无论有无钙离子，C蛋白均抑制肌动球蛋白ATP酶活性，对于去磷酸化的肌球蛋白，抑制作用更明显。对于这种肌球蛋白，在μ = 0.12时，C蛋白在pCa4时激活肌动球蛋白ATP酶，但在pCa8时略有抑制。在磷酸化肌球蛋白的情况下未观察到此类影响。讨论了LC2链和C蛋白在骨骼肌收缩调节机制中协同作用的可能性。
