Collagen

Description

The primary fibrous protein in skin, muscles, tendons, ligaments, and bone. Collagen is composed of repeating units of glycine-proline-hydroxyproline that form linear polypeptide chains. Three chains are then twisted and interlocked with hydrogen bonding to form a rigid helix structure. Collagen will irreversibly hydrolyze, or denature, in hot water. This conversion process breaks the hydrogen bonds, thus separating the strands and forming a water-soluble gelatin. Collagen containing materials, such as hides, bones and fish, have been used to make animal glues since ancient times. Tanning processes to make leather use polyfunctional phenolic materials (tannins) to crosslink, and permanently stabilize, the polypeptide chains in the collagen.

Synonyms and Related Terms

ossein; colágeno (Esp.); collagène (Fr.); collagene (It)

Physical and Chemical Properties

• Soluble in dilute acids. Insoluble in water but can be hydrolyzed with hot water to form gelatin.
• Collagen is the only protein known to contain large proportions of hydroxyproline.

Resources and Citations

• J.S. Mills, R.White, The Organic Chemistry of Museum Objects, Butterworth Heinemann, London, 1994.

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998

• Encyclopedia Britannica, http://www.britannica.com Comment: "collagen" [Accessed October 29, 2002].

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 358

• Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993

• The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 2543

• R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966

• Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982

• Mary-Lou Florian, Dale Paul Kronkright, Ruth E. Norton, The Conservation of Artifacts Made from Plant Materials, The Getty Conservation Institute, Los Angeles, 1990

• John S. Mills, Raymond White, The Organic Chemistry of Museum Objects, Butterworth Heineman, London, 2nd ed., 1994

• Book and Paper Group, Paper Conservation Catalog, AIC, 1984, 1989

• Art and Architecture Thesaurus Online, https://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000