| Popis: |
The chemistry and structure of the epidermal α-keratin extracted from the skin of patients with a variety of disorders of keratinization have been investigated using biochemical, biophysical, and electron microscopic techniques developed for the characterization of normal mammalian epidermal keratin. Generally, the α-keratin polypeptides of the diseased epidermis differed from those of uninvolved epidermis or of normal volunteers in having varying numbers of polypeptide components of lower molecular weights, numerous free amino-terminal and increased numbers of carboxyl-terminal amino acids, higher contents of α-helix, and only limited facility for polymerization in vitro into native-type epidermal keratin filaments. As the α-helix-enriched fragments, which represent up to two-thirds of the polypeptide chains, isolated after limited tryptic digestion ofthe keratin filaments of normal, uninvolved, and involved epidermis, were physicochemically identical, it seems that the end-terminal non-α-helical regions of the polypeptides of diseased epidermis are abnormal. These differences may be a result of degradation or of altered protein synthesis. |
