Keratin does not have a single, specific chemical formula. Keratin is a family of fibrous structural proteins, and its composition varies depending on the source (e.g., human hair, wool, nails).
Why Keratin Doesn't Have a Simple Formula
- Protein Structure: Keratin is a protein, and proteins are large polymers made up of amino acids. The sequence and composition of amino acids differ among various types of keratin.
- Variability: The exact amino acid composition and cross-linking patterns (disulfide bridges) differ based on the organism and the specific type of keratin being examined. This leads to variations in molecular weight and elemental composition.
- Complexity: A definitive chemical formula would need to account for all the constituent atoms of each amino acid present and the way these amino acids are linked in a specific keratin molecule. This is an incredibly complex undertaking that isn't feasible given keratin's heterogeneity.
The Chemsrc Entry: Misinformation
The Chemsrc website (https://www.chemsrc.com/en/cas/68238-35-7_1198862.html) provides the formula C2H2BrClO2 for a compound they identify as keratin. This is incorrect and misleading. This formula likely refers to a completely different, smaller chemical compound, not the complex protein keratin. You should not rely on this information.
What We Know About Keratin Composition:
While a specific formula isn't possible, we know keratin is rich in the following elements due to the amino acids it contains:
- Carbon (C)
- Hydrogen (H)
- Nitrogen (N)
- Oxygen (O)
- Sulfur (S) - from amino acids like cysteine, which forms disulfide bonds crucial for keratin's strength.
Conclusion
Keratin's nature as a complex and variable protein prevents it from having a single, definable chemical formula. Any simple formula presented as "keratin's formula" is most likely incorrect.
