The isolation and characterization of alpha-keratin microfibrils.

A method of isolating alpha-keratin microfibrils which avoids the degradation previously associated with the use of chemical, physical or enzymic procedures has been developed. Electron microscope studies of the isolation procedure establish that the microfibrils originate from the presumptive cortical cells. A purification procedure, monitored by electron microscopy, has enabled microfibrils to be isolated on a scale sufficient for chemical characterization. The amino acid composition of the microfibrils is very similar to that of low-sulphur protein fractions extracted from a range of hard mammalian keratins and thus provides direct experimental evidence for the assumption that the low-sulphur proteins comprise the microfibril in alpha-keratin.