Zobel C R
Biochim Biophys Acta. 1978 Sep 26;536(1):142-55. doi: 10.1016/0005-2795(78)90060-0.
The fragments produced by proteolysis of lobster abdominal muscle myosin with trypsin, alpha-chymotrypsin and papain have been investigated by sodium dodecyl sulfate (SDS) gel electrophoresis. Essentially monodisperse populations of long rods are produced by alpha-chymotryptic and papain digestion of rabbit myosin but corresponding digestion of lobster myosin yields multicomponent species. Similarly the low ionic strength insoluble fraction from tryptic digestion of lobster myosin is polydisperse in contrast to essentially monodisperse light meromyosin from rabbit myosin. Comparative tryptic digestion of rabbit and lobster myosin papain long rods shows that the latter have five susceptible cleavage sites in the subfragment-2 region while rabbit long rods have only one: both long rods appear to have three cleavage sites in the light meromyosin region. The fragments produced by tryptic digestion of rabbit myosin papain long rods have been tentatively identified by comparison with fragments isolated from papain digests of rabbit heavy meromyosin and tryptic digests of rabbit light meromyosin. The results suggest differences in sensitivity to enzymic proteolysis between the subfragment-2 regions in rabbit and lobster myosin as well as relative differences in proteolytic sensitivity between the subfragment-2 and light meromyosin region within the individual molecules. Partial explanation of the observation is proposed on the basis of differences in heavy chain compositions.
已通过十二烷基硫酸钠（SDS）凝胶电泳研究了用胰蛋白酶、α-糜蛋白酶和木瓜蛋白酶对龙虾腹肌肌球蛋白进行蛋白水解所产生的片段。用α-糜蛋白酶和木瓜蛋白酶消化兔肌球蛋白可产生基本上呈单分散的长杆状群体，但对龙虾肌球蛋白进行相应消化则产生多组分物种。同样，龙虾肌球蛋白经胰蛋白酶消化后的低离子强度不溶部分是多分散的，这与兔肌球蛋白基本上呈单分散的轻酶解肌球蛋白形成对比。对兔和龙虾肌球蛋白木瓜蛋白酶长杆进行的比较胰蛋白酶消化表明，后者在亚片段-2区域有五个易切割位点，而兔长杆只有一个：两种长杆在轻酶解肌球蛋白区域似乎都有三个切割位点。通过与从兔重酶解肌球蛋白的木瓜蛋白酶消化物和兔轻酶解肌球蛋白的胰蛋白酶消化物中分离出的片段进行比较，初步鉴定了兔肌球蛋白木瓜蛋白酶长杆经胰蛋白酶消化产生的片段。结果表明，兔和龙虾肌球蛋白的亚片段-2区域对酶促蛋白水解的敏感性存在差异，以及单个分子内亚片段-2和轻酶解肌球蛋白区域之间蛋白水解敏感性的相对差异。基于重链组成的差异，对这一观察结果提出了部分解释。
