Chemical preservation of protein in industrial whole animal blood

Abstract

1(NOE) is -3.93 (Witanowski and Webb, 1973). The signal to noise (S/N) enhancement will be maximum if dipoledipole interactions dominate the relaxation mechanism. If the dipole-dipole interactions are not dominant, the NOE enhancement factor will range from 1 to -3.93, proportional to the magnitude of the dipole-dipole interactions' contribution to the relaxation mechanism. In general, a single bond dipole-dipole interaction gives rise to maximum NOE enhancement. In Figure 2, the a-and c-nitrogen would be expected to have identical intensities as they do in Figure 1. The a-nitrogen signal, however, is only half that of the c-nitrogen. The binding of lysine in the polymer may alter the importance of the various relaxation mechanisms. The c-nitrogen bound in the matrix has intramolecular dipole-dipole interactions, whereas the a-nitrogen has only the intermolecular interactions which are limited in the polymer. These NOE differences are useful for deducing structural changes but make quantitation difficult. Numerous other peaks occur downfield from the urea reference and probably are from urea substituted with methylene derived from formaldehyde. No assignments have been made yet, but one could speculate that the peaks occurring at 0.4 and 1.0 ppm are due to unsubstituted urea nitrogen resonances. The peaks between 4.9-5.6 and 18.7-20.6 ppm likewise could be assigned to mono-and disubstituted urea nitrogen resonances, respectively, since substitution of electron donors larger than methyl is known to cause downfield displacement of the nitrogen resonance in ureas and amines (Witanowski et al., 1973). ACKNOWLEDGMENT We gratefully acknowledge M. J. Albright and R. 0. Obenauf of JEOL, Cranford, NJ, for taking the 15N spectra on their instrument. LITERATURE CITED Amos, H. E.; Little, C. 0.; Digenis, G. A.; Schelling, G. T.; Tucker,