The modification of the triple helical structure of gelatin in aqueous solution 3. The influence of nonionic surfactants

Abstract

Using CD-measurements the influence of nonionic surfactants (dodecyl polyoxyethylene, ethoxylated para tert. octyl phenol, commercial nonionic WON 100 and octyl diethyl phosphinoxid) on the secondary structure of gelatin in aqueous solutions was investigated. At surfactant concentrations smaller than the c.m.c, the triple helical content of the gelatin is increased. At concentrations exceeding the c.m.c, the triple helical content decreases. Chain reversals of the peptide chains after the destruction of the triple helical structure were shown to appear in acidic environment at 298 K. This destruction is reversible by rechilling the solution.

Frequency Domain Fluorescence Measurements of the Aggregation Properties of CnEm Surfactants in Agarose Gels

“…Since the aggregation number of cylindrical micelles should increase with an increase in the surfactant concentration, , an increase in the aggregation number should be expected if the gel is concentrating the micelles. This explanation is consistent with studies on C n E m surfactants in polymer solutions which exhibit segregative phase behavior. ,,,,− As the agarose fiber bundles come apart, it seems reasonable that they would also be more flexible, allowing the aggregates to push them away. In this case, there would be less restriction on aggregate growth and the thermodynamic theory presented in this work is not applicable.…”

“…This explanation is consistent with studies on C n E m surfactants in polymer solutions which exhibit segregative phase behavior. 66,80,81,83,[88][89][90][91][92][93] As the agarose fiber bundles come apart, it seems reasonable that they would also be more flexible, allowing the aggregates to push them away. In this case, there would be less restriction on aggregate growth and the thermodynamic theory presented in this work is not applicable.…”

Physicochemistry of hexadecylammonium bromide and its methyl and ethanolic head group analogues in buffered aqueous and gelatin solution

“…[21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] Interaction of gelatin with polyanions like sodium polystyrenesulfonate (NaPSS) or sodium poly(2-acrylamido-2-methylpropanesulfonate) 41 or mixed micelles of SDS and a sugar-based non-ionic surfactant 42 have been found to depend on the critical mole fraction, charge density, and chain length of the surfactants. But reports on the interaction of gelatin with non-ionic surfactants 43 or with cationic surfactants of varied types have been strikingly limited. [44][45][46][47][48] We have studied here the interaction of gelatin with the alkyltrimethylammonium bromide surfactants, and in particular the analogues of the C 16 variety having modified head groups in detail.…”

Physicochemical Studies on the Interaction of Gelatin with Cationic Surfactants Alkyltrimethylammonium Bromides (ATABs) with Special Focus on the Behavior of the Hexadecyl Homologue

“…Interaction of mixed micelles of SDS and a sugar-based nonionic surfactant with G depended both on a critical mole fraction of SDS as well as on the alkyl chain length of the nonionic surfactant . However, reports on the interaction of G with nonionic surfactants or with cationic surfactants have been strikingly limited. ,,, The standard free-energy change due to the aggregation of bound cetyltrimethylammonium bromide (CTAB) with G (at pH 5.0, μ = 0.05, 301 K) was reported to be 18.7 kJ kg −1 of biopolymer, the least among the biopolymer series studied . The prolific use of SDS to study its interaction with protein and hence G stemmed from its ability to precipitate proteins from solution under certain pHs and electrolyte solutions; precipitation from a salt-free solution at a pH lower than the isoelectric point for G has been also reported…”