Sulphure in epidermal keratohyalin granules: a quantitative assay by x-ray microanalysis.
The elemental composition of different types of keratohyalin granules from the epidermis of newborn and adult rats was studied by means of an EMMA-4 analytical electron microscope, equipped with an energy-dispersive X-ray spectrometer. An absolute quantitation of the sulphur concentration in keratohyalin granules was performed. The results demonstrate that epidermal keratohyalin granules are chemically heterogeneous. A type of keratohyalin granule present in the nuclei and cytoplasm of epidermal cells from both newborn and adult rats - termed single granules - is rich in sulphur, having a content of 2-5-3-6%. Other types of keratohyalin granules, which differ in newborn and adult rats, contain a sulphur-poor component; they often have a sulphur-rich component as well. The sulphur-poor keratohyalin contains 0-6-0-9% sulphur. It is suggested that the sulphur-rich keratohyalin granules are the source of the peripheral envelope protein of cornified cells.
D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure; D002713:Chlorine / Q000032:analysis; D003594:Cytoplasmic Granules / Q000032:analysis* / Q000648:ultrastructure; D004577:Electron Probe Microanalysis; D007633:Keratins; D010758:Phosphorus / Q000032:analysis; D051381:Rats; D012867:Skin / Q000032:analysis / Q000648:ultrastructure*; D013455:Sulfur / Q000032:analysis*; D014965:X-Rays
D010758:Phosphorus; D002713:Chlorine; D007633:Keratins; D013455:Sulfur