Synthesis of 9-O-acyl- and 4-O-acetyl-sialic acids.

Various 9-O-acyl derivatives of N-acetyl- and N-glycoloyl-neuraminic acid, and O-(5-acetamido-3,5-dideoxy-D-glycero-alpha- and beta-D-galacto-2-nonulopyranosylonic acid)-(2----6)-O-beta-D-galactopyranosyl-(1----4)-D-glucopyranose were regioselectively synthesized by use of ortho esters. In addition, 5-acetamido-4-O-acetyl-D-glycero-D-galacto-2-nonulopyranosonic acid was prepared starting from the benzyl and methyl esters of N-acetylneuraminic acid.

Isolation of Fab and Fc fragments from a plasmin-treated human immunoglobulin by high-speed gel filtration on TSK G3000SW and G3000SWG.

A method is described for isolating intact 7S IgG, Fab and Fc fragments from a plasmin-treated immunoglobulin by high-speed gel filtration on a TSK G3000SW or G3000SWG column. The isolated 7S IgG, Fab and Fc fragments reacted with antihuman IgG, Fab and Fc antiserum, respectively, in both Ouchterlony's double immunodiffusion and immunoelectrophoresis. Each of the Fab and Fc fragments formed a single precipitation line, demonstrating their homogeneity. Anticomplementary activities of intact 7S IgG, Fab and Fc fragments were 2.5, less than or equal to 10 and 2.5 mg protein/ml to inhibit 2 units of CH50, respectively, and the diphtheria antitoxin contents were 2.1, 6.0 and 1.5 IU/150 mg protein, respectively. The molecular composition of plasmin-treated immunoglobulin as determined by gel filtration on a TSK G3000SW column was as follows: 7S IgG 38.0 +/- 0.2%; Fab 42.6 +/- 0.1% and Fc fragment 19.3 +/- 0.1%.