A METHOD FOR PARTIAL-PURIFICATION OF LAMELLAR GRANULES FROM FETAL-RAT EPIDERMIS

[摘要] A subcellular fraction enriched with lamellar granules was obtained from homogenates of fetal rat epidermis by means of density gradient fractionation in metrizamide. EM showed 62% of organelles in this fraction were bound by single membranes, measuring 80-130 nm in the shorter diameter. About 10% of these had characteristic lamellae. Other structures in this fraction were larger vesicles (20%) or smaller organelles and vesicles (18%). The fraction had a low buoyant density (1.08-1.10) suggesting a high lipid content and contained a sharply localized peak of acid phosphatase activity. The 80-130 nm organelles reacted with bismuth after oxidation with periodic acid and were positive for acid phosphatase. Other intracellular organelles (e.g., lysosomes, mitochondria, ribosomes) as well as keratin fibrils and keratohyalin were not present. Most of this fraction consists of lamellar granules, permitting for the 1st time detailed investigations of the composition and metabolism of these organelles.