Biosynthesis of intestinal microvillar proteins

In the synthesis of membrane glycoproteins, the existence of a common asparagine-linked oligosaccharide intermediate, characterized by possessing a large number of mannose residues (high mannose form) has been proposed [l]. This intermediate is in turn modified by partial reglycosylation, yielding the final complex oligosaccharides, characterized by terminal sialic acid or fucose residues. Antibodies against denatured maltase-glucoamylase were prepared as follows: The pure enzyme [S] was boiled for 5 min in the presence of 1% SDS. Excess of SDS was removed by precipitation with 0.05 M KC1 (final cont.). After mixing with an equal volume of incomplete Freunds adjuvant, the der.atured enzyme was injected into rabbits (50 fig/injection) at 2 week intervals. A week after the fourth injection, the rabbits were bled for 40 ml.