Collagen acid-soluble, denatured

Banfield, A.G., Age changes in the acetic acid-soluble collagen in human skin. Arch. Pathol. 68, 680-684, 1959 Steven, F.S. and Tristram, G.R., The denaturation of acetic acid-soluble calf-skin collagen. Changes in optical rotation, viscosity, and susceptibility towards enzymes during serial denaturation in solutions of urea, Biochem. J. 85,207-210,1962 Neumark, T. 

A very interesting aspect of the reversion to collagen has arisen from the studies of Grassmann et al. (1960). They digested denatured acid-soluble collagen with trypsin and found that a number of the peptides had a three-chain structure. The denatured material must consist of single chains and chain pairs (see Section II,C) with very few triple-chain molecules. This state of affairs presumably persisted during proteolysis, and therefore the resultant peptides must then take on a heli( al form and associate to form triple-chain molecules. This demonstrates the favorableness of the three-chain structure for imino acid-rich peptides. 

Relative Proportions of the a- and 0-Components of Denatured Acid-Soluble Collagen... 

Crete components on denaturation of acid-soluble collagen is a property of collagen from all species. 

When the collagen rod can be extracted in the native form it is soluble in acidic solutions, at room temperature. If the solutions are heated, the collagen is denaturated the chains lose their helical conformation. The characteristic temperature of this helix —> coil transition is around 36 C. The solution then contains principally single chains, but also some double and triple chains which were initially covalently bound and some sub-units of the single chains. This product is gelatin. 

In this report, these concepts are applied to real proteins to collagen, an important structural material in tendons, bones, teeth, and skin, and to gelatin, the denatured product of collagen that is so important industrially. These materials are complex because of their 18 different, component amino acid side chains in addition, they present experimental difficulties because of their water solubility— they cannot be washed (e.g., with an aqueous detergent) to assure surface cleanliness. Furthermore, they are often of unknown purity. They do have the common polyamide backbone, and it is possible to transform the molecular configuration. The data are indicative of the potential utility of contact angle measurements of important, natural materials. No claim is made for adequate attention to the complex biochemistry of these materials. 

Tig. 0. Chromatograms on CM cellulose of denatured soluble collagens obtained by sequential extractions of human infant skin with 1 M NaCl, 0.5 M acetic acid (two times), and 5 M guanidine hydrochloride. The column was eluted at 40 C and pH 4.8 with a salt gradient. Note that collagens ere extracted by ecid.s and guanidine which are not extracted by salt. (Courtesy Bornstein and Piez, 1964.)... 

---