Mannose Molecules Research Articles

Characterization of collagenous and non-collagenous peptides of a glycoprotein isolated from alveoli of patients with alveolar proteinosis

A glycoprotein of Mr 62 000 was isolated from lung lavage material of patients with alveolar proteinosis. The glycoprotein was found to contain (per molecule) 72 residues of glycine, 5 residues of hydroxyproline, 3 molecules of sialic acid, 4.9 molecules of mannose, 4.0 molecules of galactose, 0.9 molecule of fucose and 7.0 molecules of N-acetylglucosamine. Limited pepsin digestion of the glycoprotein resulted in six peptides, three of which contained hydroxyproline and nearly 30% glycine, and two of which contained all the carbohydrate present in the glycoprotein of Mr 62 000. The three peptides containing hydroxyproline and with high content of glycine contained a repeating -Gly-X-Y-sequence in the peptide chain. Partial amino acid-sequence analyses on the peptides derived from the digestion of the alveolar glycoprotein with various proteolytic enzymes indicate that this glycoprotein is characterized by the presence of alternating collagenous and non-collagenous regions in the same polypeptide chain.

Structural characterization of a glycoprotein isolated from alveoli of patients with alveolar proteinosis.

A soluble glycoprotein of Mr = 80,000 has been isolated from lung lavage of patients with alveolar proteinosis and found to contain 5 residues of hydroxyproline, 91 residues of glycine, 3 residues of methionine, 3.8 molecules of sialic acid, 6 molecules of mannose, 5.9 molecules of galactose, 1 molecule of fucose, and 9.1 molecules of glucosamine. Cyanogen bromide (CNBr) treatment of the glycoprotein resulted in four peptides with molecular weights of 36,000, 27,000, 12,000, and 5,000. The chemical compositions of the CNBr peptides indicated the presence of hydroxyproline and high amounts of glycine in all but one of the peptides; two of the four CNBr peptides contained carbohydrate. Limited trypsin digestion of the glycoprotein of Mr = 80,000 resulted in four peptides with molecular weights of 62,000, 36,000, 26,000 and 18,000, the latter being the NH2-terminal peptide of the native glycoprotein molecule. The peptide of Mr = 26,000 was found to be the COOH-terminal peptide.

A study of the 11S globulin from cotton seeds IX. Structure of the glycopeptide

1. The oligosaccharide of the glycopeptide (I) from subunit C of the 11S globulin of cotton seeds consists of one molecule of glucosamine and three molecules of mannose.

On the structure of the carbohydrate chains of different strains of the influenza virus

Structural features of the glycosyl chains of the influenca virus have been determined. It was found that fucose was solely terminal, whereas mannose and galactose were present at the terminal as well as subterminal and core positions. Mannose and glucose molecules were shown to be branching points in the glycosyl chains. Furthermore, linkage positions of carbohydrates within the chains were characterized.

Some properties of a lipase from Rhizopus arrhizus separation of a glycopeptide bound to the enzyme

The exocellular lipase from Rhizopus arrhizus is a glycoprotein of molecular weight around 43 000, containing 13–14 molecules of mannose and 2 molecules of hexosamine and a single N-terminal aspartic acid residue (or asparagine). This lipase (lipase I) consists of 2 apparently noncovalently linked portions: a glycopeptide of molecular weight around 8500 and the enzyme protein. This latter can be easily freed from the glycoprotein by heating or by precipitation in the cold with 5% trichloroacetic acid. The glycopeptide does not play any role in the catalytic function of the enzyme. Upon long storage of lipase I, this glycopeptide separates and lipase I is converted into a second active form, lipase II. This slow separation is paralleled by a fragmentation of the glycopeptide into peptides and shorter glycopeptides. The enzymic protein also seems to be partly degraded as shown by the disappearance of the single N-terminal aspartic acid (or asparagine) residue and the appearance of several other N-terminal residues in non-stoichiometric proportions.