Polypeptides collagen

Since collagen is a secreted protein, we know that it must follow the route of synthesis that starts on a ribosome bound to the endoplasmic reticulum (fig. 29.23). This is where the fun begins, as we find that the nascent collagen polypeptide has extensive N and C termini (150 and 250... 

Paterlini, M. G., Nemethy, G., and Scheraga, H. A. (1995). The energy of formation of internal loops in triple-helical collagen polypeptides. Biopolymers 35, 607-619. 

Once this domain is removed, refolding of the three collagen polypeptides to the correctly staggered molecules is very difficult or impossible. The folding reaction from three polypeptides into a triple helix is affected by the concentration of the peptides. For the kinetic refolding analysis of triple helical model... 

Italic type indicates the various collagen polypeptides and an enzyme mutation described in this... 

Structure of tropocollagen. (a) The coiling of three left-handed helices of collagen polypeptides. The dotted lines indicate hydrogen bonds, (b) The right-handed triple-stranded superhelix. The curved arrow indicates the covalent linkage between two chains. [Reproduced with permission from I. Geis and R. E. Dickerson.]... 

The results showed that while none of the books stored in the clean Welsh environment had deteriorated to any significant extent, nearly all the volumes subjected to London s acidic pollution exhibited evidence of decay, some within less than 10 years. In addition, the superior ageing properties of leathers prepared with hydrolysable tannins were confirmed. Of the various chemical analytical determinations undertaken, the only results to show any correlation with the degree of deterioration observed were those for the number of -terminal amino acid groups on the protein. This figure reflects the amount by which the collagen polypeptide chain had been broken and was considered to be evidence for hydrolytic deterioration. 

Cationic Collagen Polypeptides. [May-brotd ] Cationic collagen polypepdd substantivi agent, film former, protective colloid for hair and skin care prods. 

The cross-linkages found in collagen and elastin arise from the non-enzymatic interaction of a-amino adipic acid 8-semialdehyde (AL) and 8-hydroxy a-amino adipic acid 8-semialdehyde (HAL) with another residue of the aldehyde or with lysine, hydroxylysine, or histidine residues located at specific positions in the collagen polypeptide chains. Possible relationships among the different compounds in Table II are shown in Figures 4 and 5 for collagen and elastin. 

An individual collagen polypeptide chain has a large number of repeating amino acid sequences, most often glycine-X-Y, where X is often proline and Y is often hydroxyproline. Lysine, in its pure form or modified to hydroxylysine, is also found in collagen. Both hydroxyproline and hydrox-ylysine are formed via the enzyme-catalyzed oxidations of the profine and lysine amino acid side chains, which occur after the collagen polypeptide has been synthesized. These enzymatic reactions reqtiire ascorbic acid (vitamin C) as a cofactor. 

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