Occurrence of ‘Ester-Like’ Linkages in Collagen

ALTERATIONS IN STATE OF MOLECULAR AGGREGATION OF COLLAGEN INDUCED IN CHICK EMBRYOS BY SS-Aminopropionitrile (LATHYRUS FACTOR)

“…Whether or not intermolecular bonds of higher energy such as amide or ester links might form in the course of time is not known. There is some evidence to suggest the existence of such bonds within the molecule (49,50). Veis and Cohen (51) believe covalent cross-links between molecules are required to explain certain solubility properties of gelatin.…”

The Ageing of Collagen in the Striated Muscle

“…Such connections may be established on the e-amino group of lysine rests in an amide-like fashion (Mechanic and Levy, 1958) 30. Esterbonds were proved by the reaction with hydroxylamine (Gallop et al, 1959) 23. Grassmann and coworkers suppose that the bridges are built by neutral carbohydrates (Hormann, 1960)31.…”

Reaction of Certain Aliphatic Aldehydes with Gelatin

“…However, the additional facts that these compounds have little or no effect on the reaction once initial aldehyde attack has occurred and that only hydrazine and hydroxylamine, which act by cleaving ester-like bonds (Gallop et al, 1959) and/or -C = C-bonds (Sayigh, Ulrich and Green, 1964) and/or amide bonds {de la Burde et al, 1963), can inhibit the reactions thereafter strongly suggests that the hydrated aldehydes do in fact form highly crosslinked polymer networks with randomly coiled gelatin chains.…”

“…Alternatively, it is also possible that bipointal "ester-like" linkages (one end being ester hemiacetal and the other glycosidic) can be formed by hydrated aldehydes between the carboxyl groups of aspartyl residues (Gallop et al, 1959(Gallop et al, , 1964Blumenjeld et al, 1963).…”