The association of lipids with keratinous proteins of human callus.

ABSTRACT

1. Small amounts of phospholipids and cho- lesterol bound to major callus protein fractions during extraction have been quantitated. 2. Extraction with chloroform/methanol abolishes the requirement of these protein fractions for prolonged acid hydrolysis in order to release completely certain amino acid residues. 3. The binding capacity of lipid-free, isolated, keratinous proteins for cholesterol has been studied. 4. A plausible (though unproven) role for phospholipids, cholesterol, and keratin in the barrier functions of epidermis is re-emphasized.