Hair
Composition

Hair is mainly composed of keratin proteins and keratin-associated proteins (KRTAPs). The human genome encodes 54 different keratin proteins which are present in various amounts in hair. Similarly, humans encode more than 100 different KRTAPs which crosslink keratins in hair. The content of KRTAPs ranges from less than 3% in human hair to 30–40% in echidna quill.
keywords:existence, oulipo:avoid_letter[o]