Vergleichende optische Untersuchungen an modifizierten Gelatinen und an Kalbshautkollagen

Einfluß der Modifizierung auf das konformative Verhalten

Abstract

Results of optical measurements (UV and CD) on gelatin with intracatenar cross-links, on a number of otherwise modified gelatins and on citrate-soluble calf skin collagen in dependence of the temperature are presented. From these results, especially from CD measurements, conclusions as to the amount of helical chain segments in very diluted solutions at low temperature can be drawn. The degree of helicity depends on the average molecular weight as well as on chemical modification.

The strongest inhibition of helix formation in undegraded gelatin resulted from intracatenar cross-linking, as it has been described in a previous paper. Helicity in degraded gelatins depends not only on the average molecular weight (M_n) but also on the conditions of degradation (alcaline, acidic, oxydative). Though gel formation of more concentrated gelatin solutions is a result of reforming helical structures, the relation between optically determined helicity in dilute solutions and the gel melting points of 2 to 4% solutions differs with the preparations here investigated. No simple, uniformly valuable correlation between the two values was found.