Keratin

The document discusses the complexity of keratin as a biomaterial, emphasizing that hair follicles are composed of various types of keratins and keratin associated proteins (KAPs) that self-assemble into a molecular composite with distinct compartments like the cortex and cuticle. It highlights the importance of understanding the physical arrangement, interactions, and composite nature of keratin fibers for designing effective extraction and purification protocols. The keratins in hair are particularly noted for their high cysteine content and the extent of disulfide crosslinking, which is significant for their properties. The document also mentions oxidative sulfitolysis as a method for processing keratin, which is a hybrid chemical process involving both oxidation and reduction.