Baden H P
Curr Probl Dermatol. 1980;10:345-63. doi: 10.1159/000396300.
The subunit structure of prekeratin has been studied by examining the products formed after proteolytic digestion and site-specific cleavage at cysteine and cystine residues. The monomer unit of prekeratin consists of 3 polypeptides which contain a helical segment of 34,000 daltons. This segment appears to consist of 2 helical polypeptides separated by a non-helical one, and the helical polypeptides in turn contain 2 smaller segments of about 7,000 daltons. Cysteine residues are not localized to one region of prekeratin, but are evenly distributed in the molecule; this suggests that they may be located in the nonhelical regions. The polypeptide composition of keratins has been studied by SDS polyacrylamide gel electrophoresis, and heterogeneity in the polypeptide components can be demonstrated between species, within a species, and in different areas of skin of a single member of species. The pattern of keratin polypeptides, furthermore, is not fixed but can be altered by changes in the cellular environment.
通过研究蛋白水解消化以及在半胱氨酸和胱氨酸残基处进行位点特异性切割后形成的产物，对前角蛋白的亚基结构进行了研究。前角蛋白的单体单元由3种多肽组成，这些多肽包含一个34,000道尔顿的α螺旋片段。该片段似乎由2个由一个非螺旋多肽隔开的螺旋多肽组成，而螺旋多肽又包含2个约7,000道尔顿的较小片段。半胱氨酸残基并不局限于前角蛋白的一个区域，而是均匀分布在分子中；这表明它们可能位于非螺旋区域。通过SDS聚丙烯酰胺凝胶电泳研究了角蛋白的多肽组成，并且可以证明在不同物种之间、同一物种内以及同一物种单个成员皮肤的不同区域中，多肽成分存在异质性。此外，角蛋白多肽的模式不是固定的，而是可以通过细胞环境的变化而改变。
