Marianne-Pépin T, Mornet D, Audemard E, Kassab R
FEBS Lett. 1983 Aug 8;159(1-2):211-6. doi: 10.1016/0014-5793(83)80448-7.
The reaction of trypsin on the heavy chain of gizzard myosin and chymotryptic HMM was investigated under restricted fragmentation conditions. The three fragments of the head part with 29 kDa, 50 kDa and 26 kDa were isolated and identified. The 66 K heavy chain segment containing the S1-S2 junction was slowly but extensively degraded liberating a S1-like entity which lacked an intact COOH-terminal 26 kDa region; this isolated species displayed full intrinsic ATPase activities but little actin-binding ability. Tryptic HMM was also formed bearing a fragmented heavy chain and lacking the 20 kDa light chain. Its actin-activated ATPase was derepressed upon cleavage of the 66 kDa segment by papain. We propose that the integral 66 kDa heavy chain component is directly involved in the regulation of the gizzard actomyosin ATPase.
在有限片段化条件下，研究了胰蛋白酶对砂囊肌球蛋白重链和胰凝乳蛋白酶处理的重酶解肌球蛋白（HMM）的反应。分离并鉴定了头部的三个片段，分别为29 kDa、50 kDa和26 kDa。含有S1 - S2连接点的66 K重链片段缓慢但广泛地降解，释放出一个缺乏完整COOH末端26 kDa区域的类似S1的实体；这个分离出的物种显示出完全的内在ATP酶活性，但肌动蛋白结合能力较弱。还形成了带有片段化重链且缺少20 kDa轻链的胰蛋白酶处理的HMM。木瓜蛋白酶切割66 kDa片段后，其肌动蛋白激活的ATP酶被解除抑制。我们认为完整的66 kDa重链成分直接参与砂囊肌动球蛋白ATP酶的调节。
