Variation of the distribution pattern of SH groups and SS linkages in the human epidermis.

Normal epidermis of various sites of human body was examined by N-(7-dimethylamino-4-methyl-3-coumarinyl)maleimide (DACM) method for SH groups and SS linkages. The horny cells in the palm and sole showed a gradual occurrence of a SH membranous pattern, while those in other sites revealed an abrupt formation of the SH membranous pattern just above the granular layer. In the palm and sole epidermis the number of layers which exhibit membranous pattern of SH-positivity was thicker than that in the other other epidermis; the low- through mid-layers of horny cells in the former sites seemed to contain not only SS-positive but also SH-positive substance at cell peripheries. The DACM staining for SS linkages showed the presence of a granular fluorescence in the cytoplasm of the granular cells of the granular cells of the epidermis in the human palm and sole, but not in other sites. The granular cells in human lip displayed a granular fluorescence in the cytoplasm of the granular cells of the epidermis in the human palm and sole, but not in other sites. The granular cells in human lip displayed a granular fluorescence in the cytoplasm by either SH or SS DACM staining. All the SH- or SS-positive granular fluorescence was related to keratohyaline granules. These findings indicate that there may be some variations of the distribution pattern of the epidermal cellular proteins with SH and/or SS and a difference in chemical composition of keratohyaline granules between different anatomical sites of human body.