The cystine-rich envelope protein from human epidermal stratum corneum cells

A cystine-rich protein has been extracted from the membrane region of stratum corneum cells with 50 mM Tris-HCl buffer, pH 7.3. The protein has been purified by molecular sieve chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and preparative isoelectric focusing. An antibody, raised to the purified protein, was located in the cell membrane region in the stratum spinosum, stratum granulosum, and the inner part of the stratum corneum. In addition, the antibody also reacted with the protein extracted from the outer part of the stratum corneum by the immunoblotting method. Amino acid analysis of the protein revealed a distribution of 4.3% cystine residues, 9% lysine, 18.5% glycine, and 12.6% glutamic acid residues. The isoelectric point was found to be 4.8 and the molecular weight of the protein was 16,000.