THE ISOLATION OF AN UNREDUCED SOLUBLE OVOMUCIN By DAVID S. ROBINSON* and JOHN B. MONSEY

1. New preparations of reduced carboxymethylated /3-ovomucin (S-carboxymethylf,-ovomucin) were homogeneous by sedimentation analysis, analytical sedimentation to equilibrium in CsCI gradients, and disc electrophoresis in sodium dodecyl sulphate. 2. Degradation of S-carboxymethyl-f/-ovomucin with either CNBr or trypsin indicated the presence of a subunit (approx. mol.wt. 112300). 3. Electron microscopy showed that S-carboxymethyl-fi-ovomucin consisted of chains of globular units (approx. mol.wt. 103000). In 6M-guanidinium chloride S-carboxymethyl-fl-ovomucin existed mainly as an aggregate (mol.wt. 720000). 4. S-Carboxymethyl-,B-ovomucin contained ester sulphate (4.24%, w/w) and carbohydrate (60%, w/w), which consisted of large amounts of galactose (22%, w/w), galactosamine (8.9%, w/w) and sialic acid (10.6%, w/w). 5. An unreduced soluble fibrous component (component SGH) extracted from crude ovomucin precipitate with 5M-guanidinium chloride contained fl-ovomucin (approx. 70%, w/w). By using the Scheraga-Mandelkem equation the molecular weight ofcomponent SGH was calculated to be 11.5 x 106.