Gelatin mutarotation

D-, mutarotation kinetics, 57 Gelatin, mutarotation of, 13 j3-Gentiobiose, octaacetate, 264 Glucal, 2-acetoxytri-O-acetyl-D-, oxo reaction with, 92... 

A perusal of the data of Smith discloses that the specific rotation of 24-hr, low temperature gelatin is remarkably insensitive to protein concentration, in contradistinction to the direct relationship between mutarotation and chain association which some workers have assumed in the past (Kraemer and Fanselow, 1925 Katz, 1933). The independence of the two processes is also indicated by the investigations of Ferry and Eldridge (1949). On chilling ossein, alkali-processed gelatin solutions of various concentrations (2-6% protein), each solution attained virtually the same specific rotation ([a]s46 = —375°) after 24 hr. Moreover, the melting-out profiles of all of the solutions were essentially coincident, with [a] we declining... 

Although the rate of mutarotation of cold dilute gelatin is independent of protein concentration, kinetic analysis reveals an exponential dependence of d[a]/dl on the concentration of chain elements in the unfolded form. Thus van t Hoff plots of log (d a]/dt) versus log ([ ] —[ ]<), derived from the general equation ... 

Fig. 25. Initial rate of mutarotation of ichthyocol gelatin cooled to 4°C at zero time, as a function of ionic strength (CaCU). (From von Hippel and Wong, 1961.)...

The poly-L-proline II configuration propagates outward from these nuclei along single gelatin chains. This process is responsible for the more rapid, concentration-independent portion of the mutarotation phenomenon. 

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