Wool Chemical Composition and Keratin Structure
topic
Wool keratin composition: 18 amino acids with cysteine (10-17% providing disulfide crosslinks), glutamic acid (11-16%), serine (9-11%), glycine (6-9%), leucine (7-9%), and others. Chemical components: α-keratin protein 95-97%, lipids (wool wax, fatty acids) 1-2%, mineral matter 0.5-1%, moisture (equilibrium regain 16-18% at 65% RH). Disulfide bonds (1 per 10 amino acids) provide strength and stability; hydrogen bonds contribute elasticity; salt linkages stabilize structure.
Role
High cysteine content enabling abundant disulfide crosslinks provides chemical stability, elastic recovery (99% at 2% extension), and enables permanent set treatments (perming, steam setting) while making wool susceptible to oxidizing agents (chlorine bleach causes yellowing and weakening).