Role of Oligosyl Residue of Glycoprotein Solution in Viscosity Behavior

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Deglycosylated A_1 ovalbumin with two phosphoryl residues in the molecule was prepared from native A_1 ovalbumin by endo-beta-N-acetylglycosamidase treatment and successive affinity chromatography using various lectin agarose columns. Native ovalbumin is not susceptible to be hydrolyzedby trypsin, however, deglycosylated ovalbumin was limited-hydrolyzed, being shown by SDS polyacrylamide gel electrophoresis. The new fragments appeared with the digestion of trypsin had about 30,000 and 10,000 of molecular weight estimated. Using the differential scanning calorimetric meassurement, the denaturation temperature of the deglycosylated A ovalbumin was 71.8^ﾟC which was lower than that of the A_1 ovalbumin by 0.8^ﾟC. A and deglycosylated A_1 ovalbumin (0.40 mg/mL) have different turbidity-pH profiles. The peak of deglycosylated ovalbumin was found at pH and the endothermic area was broader than that of the A_1 ovalbumin, indicating the hydrophobicity of A_1 ovalbumin decrease by deglycosylation.Non-glycosylated ovalbumin was purified from the oviduct of the hen to which tunlcamycin was injected. Non-glycosylated ovalbmin and glycosylated ovalbumin was purified with a combination of the crystalization and lectin column chromatography. Non-glycosylated ovalbumin obtained from the hen injected tunicamycin was a different phosphorylated pattern. That is, the ratio of the A_1, A_2, and A_3 ovalbumin was changed. Non-glycosylated and glycosyslated A_1 ovalbumin were separated and isolated by DEAE cellulose chromatography. The apparent viscosity of non-glycosylated A_1 ovalbumin solution was higher in a low shear rate region than that of glycosylated A_1 ovalbumin solution. This means that the glyco part of the glycoprotein reduces the viscosity at low shear rate region. Non-glycosylated A_1 ovalbumin showed low heat stability and high susceptibility to trypsin.