Gelatin collagen transformation

The collagen gelatin transformation in solution has been recognized as a reversible first-order phase transition, subject to the same physical laws which govern the crystalline amorphous phase transitions observed in systems of linear polymers. The direct relationship between the transition in solution and the well-known thermal shrinkage phenomenon exhibited by collagen fibers has also been established. 

Following on this many other authors have found it necessary to assume cross-links in collagen in order to explain the results of studies on the collagen —> gelatin transformation (Gustavson, 1955b,c Veis and Cohen, 1956 Veis et al., 1958 Courts, 1960). Veis et al. (1958) have discussed the differences between acid-processed and alkali-processed gelatins in... 

The film prepared at 50 C differs in that it no longer contains the triple helix structure. If the helix-coil (or collagen gelatin) transformation is complete, the absorption should no longer be related to the different structural levels but instead controlled by the tortuosity of the diffusion paths. The rate of water absorption is considerably slower with a decrease in the weight absorbed at low humidities. But the energy profile remains similar to the sample prepared at 20 C. We believe that the disappearance of the triple helix structure is incomplete and that the water tends initially to be absorbed by the structures still present. 

Chein, J. C. W., and Wise, W. B. (1975). Biochemistry 14, 2786. A 1 3C Nuclear Magnetic Resonance and Circular Dichroism Study of the Collagen-Gelatin Transformation in Enzyme Solubilized Collagen. 

To investigate this idea, Esipova (1957) and Doty and Nishihara (1958) examined the temperature at which solutions of various types of collagen were transformed to gelatin, and compared these measurements of T with thermal shrinkage temperatures obtained by Gustavson and others. 

Cationized gelatin has been used in vivo to mediate vector-based RNAi in a murine model of obstructive nephropathy after intraureteral delivery. Administration of a plasmid encoding siRNA against the transforming growth factor-(3 (TGF-P) receptor gene resulted in a reduction in collagen content and fibrotic... 

In this report, these concepts are applied to real proteins to collagen, an important structural material in tendons, bones, teeth, and skin, and to gelatin, the denatured product of collagen that is so important industrially. These materials are complex because of their 18 different, component amino acid side chains in addition, they present experimental difficulties because of their water solubility— they cannot be washed (e.g., with an aqueous detergent) to assure surface cleanliness. Furthermore, they are often of unknown purity. They do have the common polyamide backbone, and it is possible to transform the molecular configuration. The data are indicative of the potential utility of contact angle measurements of important, natural materials. No claim is made for adequate attention to the complex biochemistry of these materials. 

Pavne, K.J. and Veis, A. (1988) Fourier transform IR spectroscope of collagen and gelatin solutions Dccon volution of amide I band for conformational studies. Biopolymers, 27, 1749-1760. 

---