PubMed Health⌕ Search

Biomedical subjects

F Downs

Publications and source records attributed to F Downs.

12 recordsLinked to original sources
PubMed1977

Chemical studies on a hamster sublingual glycoprotein.

A secretory glycoprotein was isolated from the hamster sublingual gland. It contains 65% carbohydrates, the remainder being protein. The principal type of sialic acid was identified as N-acetylneuraminic acid with about 1/4 of the molecules O-acetylated. The hexosamine occurs mainly as N-acetylgalactosamine; other sugars present are galactose and fucose. The carbohydrate side chains are linked to the protein core by an O-glycosyl linkage between seryl and threonyl residues and N-acetylgalactosamine. The glycoprotein has an apparent molecular weight of 330,000. The sialogly coprotein may act as a biological antifreeze. Relevant differences in the chemical composition of the secretory glycoproteins of the sublingual and submaxillary salivary glands of this species are briefly discussed.

Amino Acids↗
PubMed1977

Quantitation of the beta-elimination reaction as used on glycoproteins.

The carbohydrate side chains of mucus-type glycoproteins are O-glycosidic bonds between N-acetylgalactosamine to the hydroxyl groups of serine and threonine in the protein core. The alkaline catalyzed beta-elimination reaction, in the presence of sodium borohydride, is used for determining the number of side chains. The present paper presents a study of the quantitativeness of the alkaline borohydride procedure, using four parameters: the loss of seryl and threonyl residues, the formation of alanine and 2-aminobutanoic acid; the decrease in N-acetylhexosamine and the recovery of the amino sugar alcohols. Bovine, ovine and porcine submandibular glycoproteins were studied. Evidence is presented for the existence of N-acetylglucosamine involvement in O-glycosidic linkages to serine and threonine. Results for the relative rates of beta-elimination indicate that serine-linked glycosides are released more rapidly than threonine-linked glycosides.

Alanine↗