1981 年 21 巻 4 号 p. 219-226
It is generally believed that myosin subfragment-1 (S-1) is the segment of the myosin molecule that catalyzes the hydrolysis of ATP and thereby impels actin. So the structure and "internal mechanics" of S-1 assume great importance in clarifying the molecular mechanism of the sliding theory of muscle contraction, Group with various suggestive functionalities (reactive thiols, a reactive lysine, reactive arginines, certain tryptophans, etc.) reside on S-1. The limited tryptic digestion of the heavy chain of S-1 results in three major peptides with approximate molecular weight of 50K, 27K, and 20K, without much additional protolysis. This method opens a new line of ilvestigation. Locating known functionalities and their proximities among the peptides are eafly step in this line.
In the tryptic digestion of S-1, 27 K-peptide is generated by two parallel routes: directly from the 75K-peptide, and through a 29.5K-peptide precursor. A reactive lysyl residue is present in both the 27K-and 29.5K-peptides. However, the reactivity of these lysyl residue differ. This indicates that the two routes of generating the 27K-peptide correspond to the proteolysis of two different heavy chains of S-1.