Abstract
It is well known that bovine immune lactoglobulin of cow colostrum contains carbohydrate which is tightly bound to some unknown part of the molecule. Our study was initiated to know the exact nature of the carbohydrate and its mode of linkage to the polypeptide chain of immune lactoglobulin.
Bovine immune lactoglobulin was isolated from skim colostrum by precipitation procedure with ammonium sulfate. Glycopeptide was prepared from heat denatured immune lactoglobulin by repeated digestion with proteinase (pronase-P). The glycopeptide was isolated from the digested material by gel filtration on Sephadex G-25 and G-50. It was then fractionated into five components with DEAE cellulose chromatography. Judging from hexose recovery, about forty six percent of the total hexose was recovered from the pronase digest. One of the components contained 2.8% of nitrogen, 65.5% of hexose, 6.7% of fucose, 27.5% of glucosamine and 1.4% of sialic acid, while the other components contained more nitrogen and less carbohydrate. The ratio of hexose and sialic acid content was also remarkably different among the five components.
