nounIntermediate
Definition
Family of fibrous structural proteins that form the primary component of hair, nails, horns, hooves, and the outermost layer of skin (stratum corneum).
Detailed Explanation
Family of fibrous structural proteins that form the primary component of hair, nails, horns, hooves, and the outermost layer of skin (stratum corneum). Keratins are divided into type I (acidic, K9-K28) and type II (neutral/basic, K1-K8, K71-K86). They are characterized by high cysteine content forming extensive disulfide cross-links that give tissues mechanical strength. Hair α-keratin forms coiled-coil dimers that wind into protofibrils, protofilaments, and ultimately macrofibrils. Keratin is insoluble and resistant to most proteases — which is why hair and nails persist after death.
Key Facts
- Family of fibrous structural proteins that form the primary component of hair, nails, horns, hooves, and the outermost layer of skin (stratum corneum).
- Keratins are divided into type I (acidic, K9-K28) and type II (neutral/basic, K1-K8, K71-K86).
- They are characterized by high cysteine content forming extensive disulfide cross-links that give tissues mechanical strength.
- Hair α-keratin forms coiled-coil dimers that wind into protofibrils, protofilaments, and ultimately macrofibrils.
- Keratin is insoluble and resistant to most proteases — which is why hair and nails persist after death.
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