Keratin Biot

Keratin composes all parts of a feather and sometimes forms a thin flat strip that is similar to a barb, but termed a biot. A tough, fibrous protein molecule, keratin contains significant amounts of sulfur-containing amino acids, especially cysteine. Disulfide bridges formed between sulfur atoms in filaments of keratin, which are helical in shape, are largely responsible for the relative rigidity of the protein, which is insoluble in water and resistant to enzymes that are able to cleave most other protein molecules. Keratin does, however, breakdown when exposed to sulfuric acid, yielding the nitrogenous substances leucin and tyrosin. In addition to feathers, keratin is the primary structural component of hair, claws, horns, reptile scales, and baleens, the sieve-like structures some whales use to filter food particles from surrounding water.


© 1995-2013 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, software, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.
This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.
Last modification: Tuesday, Jan 06, 2004 at 11:16 AM
Access Count Since January 19, 1999: 23486
Microscopes provided by:
Visit the Nikon website. Visit the Olympus Microscopy Resource Center website.