Ester-Like Linkages in Collagen

Ester links between threonine and the terminal carboxyl of a peptide chain forming a lactone have been found in actinomycin (Bullock and Johnson, 1957), while Dekker et al. (1949) have found an imide link in the form of a pyrrolidonyl ring involving the N-terminal glutamic acid residue in a peptide isolated from algae. In teichoic acids (polymers present in 

Phosphodiester cross-links have been identified in d-casein and pepsin (Perlmann, 1954). Ester cross-links in elastin via hexoses have l een suggested, on little evidence, by Walford et al. (1961). 

The structures of some of these linkages are given in h ig. 8. Kelatively few proteins, or even peptides, have been shown to have ester-like linkages incorporated into their structure. The evidence for such links in collagen will now be reviewed. 

Ester linkages in collagen were first proposed by Sc.hneider (1949) as the means by whi( h sugar bridges were incorporated into the peptide chain. Th( first real evidence for ester linkages in collagen was obtained by Grass- 

Simple ester link from the oi-carboxyl of aspartic or glutamic acids to the hydroxyl group of any hydroxyamino acid 

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Determination of Ester-Like Linkages in Collagen and Gelatin Using Hydroxylamine... 

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