Demonstration of heterogeneity of chick ovalbumin glycopeptides using 360-MHz proton magnetic resonance spectroscopy.

Ovalbumin glycopeptides AC-C and AC-D at various stages of purification were studied by high-field proton magnetic resonance spectroscopy (1H NMR). In a homogeneous substance, the intensity of the various resonances appears in integral amounts, while subintegral intensities usually denote mixtures of structure. We show how 1H NMR can be used to nondestructively assay the purification of major components from mixtures. In glycopeptide AC-C we have spectroscopic evidence for the four different glycopeptide species, three of which have been described [Shepherd, V., & Montgomery, R. (1978) Carbohydr. Res. 61, 147; Tai, T., Yamashita, K., Ito, S., & Kobata, A. (1977) J. Biol. Chem. 252, 6687]. However, we did detect a fourth structure not previously reported. In glycopeptide AC-D, we have spectroscopic evidence for five different compounds, only two of which have been previously reported (Tai et al., 1977; Shepherd & Montgomery, 1978).