Isolation and characterization of a variant of ovomucoid.
A simple procedure, which can be used on a preparative scale, for the isolation and purification of a major variant of ovomucoid from egg white is described. Ovomucoid was precipitated by salt, and further fractionated by chromatography on sulphoethyl-Sephadex. It showed size homogeneity as revealed by gel chromatography and sodium dodecyl sulphate-polyacrylamide-gel electrophoresis where the mobility was consistent with a molecular weight of 28 300+/-2300. The inhibitor showed full antiryptic but no antichymotryptic activity. The u.v.-absorption and fluorescence characteristics indicated the absence of tryptophan. Polyacrylamide-gel electrophoresis in the presence of 9M-urea demonstrated absence of charge heterogeneity. The intrinsic viscosity of ovomucoid was 5.36ml/g which yielded an equivalent hydrodynamic radius (2.9nm), axial ratio (6.0) and frictional ratio (1.31) of the molecule. The Stokes radius (3.5nm), diffusion coefficient (7.8 times 10(-7 cm2/s) and frictional ratio (1.35) were calculated from gel-filtration data. These results suggest that ovomucoid exists in non-globular conformation under native conditions and that the deviation from the behaviour of a typical globular protein seems to be due both to asymmetry and hydration.
D000818:Animals; D011232:Chemical Precipitation; D002645:Chickens; D002850:Chromatography, Gel; D004527:Egg Proteins / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D008970:Molecular Weight; D010047:Ovalbumin / Q000032:analysis; D010059:Ovomucin / Q000032:analysis / Q000302:isolation & purification*; D011487:Protein Conformation; D012212:Rheology; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014364:Tryptophan / Q000032:analysis; D014508:Urea; D014783:Viscosity
D004527:Egg Proteins; D010059:Ovomucin; D014364:Tryptophan; D014508:Urea; D010047:Ovalbumin