1. Keratins are considered examples of scleroproteins or Albuminoids

2. In all amniotes specialized intermediate filament keratins (IF-keratins), in addition to keratin-associated and Corneous proteins form the outermost cornified layer of the epidermis.

3. Low-angle X-ray diffraction is a powerful means of investigating the microfibril-matrix-complex ofα-keratins.

4. Cystine definition, a crystalline amino acid, C6H12O4N2S2, occurring in most proteins, especially the keratins in hair, wool, and horn, and yielding cysteine on reduction

5. Cystine definition is - a crystalline amino acid C6H12N2O4S2 that is widespread in proteins (such as keratins) and is a major metabolic sulfur source.

6. Setae are composed of interlaced Corneous bundles made of small cysteine‐glycine‐rich Corneous beta proteins (CBPs, formerly indicated as beta‐keratins), embedded in a matrix material composed of cytoskeletal proteins and lipids.