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A Hamada

Publications and source records attributed to A Hamada.

At least 127 records · Page 7Linked to original sources
PubMed1981

Isolation and structural studies of the neutral oligosaccharide units from bovine glycophorin.

The O-glycosidically linked carbohydrate units of glycophorin from bovine erythrocyte membranes were released as reduced oligosaccharides by alkaline borohydride treatment. These oligosaccharides were separated by ion-exchange chromatography followed by gel filtration. Three oligosaccharides, a penta- a hepta- and a decasaccharide were obtained as the major components from the neutral fraction, and seven fractions were separated from the acidic fractions. All of the fractions were found to contain galactose and N-acetylglucosamine in variable amounts, as well as N-acetylgalactosaminitol. Studies of the neutral oligosaccharides by methylation analyses, nitrous acid deamination and Smith degradation, indicated the structure of the pentasaccharide to be Gal(1 leads to 3)Gal(1 leads to 4)GlcNAc(1 leads to 3)GalNAcol and that of the heptasaccharide to be Gal(1 leads to 3)Gal(1 leads to 4)GlcNAc(1 leads to 3)Gal(1 leads to 4)GlcNAc(1 leads to 3)Gal(1 leads to 3)GalNAcol. The highest molecular weight fraction, decasaccharide in the neutral fraction had a branching point at C-6 of a galactose residue.

Animals↗
PubMed1981

Isolation and characterization of two glycophorins from horse erythrocyte membranes.

Crude glycophorin fraction was prepared from horse erythrocyte membranes by extraction with lithium diiodosalicylate and partition in aqueous phenol. Two glycophorins, designated glycophorins HA and HB, were isolated by two different techniques: preparative gel electrophoresis in the presence of sodium dodecyl sulfate and ion-exchange chromatography in the presence of the nonionic detergent Ammonyx LO. Each glycophorin formed at least two bands on gel electrophoresis, which corresponded to a dimeric form and a monomeric form. Glycophorin HA, the major component, had a blocked amino-terminus and consisted of 70% protein and 30% carbohydrate. Glycophorin HB, the minor component, had threonine as the amino-terminus and consisted of 80% protein and 20% carbohydrate. Since glycophorin HB showed a chemical composition distinct from that of glycophorin HA, glycophorin HB was not a partially degraded form of glycophorin HA.

Amino Acids↗
PubMed1981

Isolation and partial structural characterization of macroglycolipid from rabbit erythrocyte membranes.

A macroglycolipid containing galactose and N-acetylglucosamine as predominant sugar constituents was prepared together with glycophorin from rabbit erythrocyte membranes by extraction with lithium diiodosalicylate and partition in aqueous phenol. The macroglycolipid was effectively separated from the glycophorin fraction by ion-exchange chromatography in the presence of a detergent, Ammonyx LO. Its yield (ca. 4 mg/100 ml erythrocytes) was significantly higher than that of the macroglycolipids from human erythrocytes. The structure of the carbohydrate moiety in the macroglycolipid was analyzed by methylation analysis, Smith degradation, nitrous acid deamination, and chromium trioxide oxidation. Assuming one ceramide residue per molecule, the average number of sugars in the macroglycolipid was about 30. The macroglycolipid had a highly branching structure: Gal(alpha 1 leads to 3)Gal(beta 1 leads to 4)GlcNAc sequences are present at nonreducing termini and leads to 3 Gal(beta 1-4)GlcNAc repeating units are present in the inner core of the sugar chain. Some of the inner galactose residues branch at the C-6 position. Constituents of the ceramide moiety were also characterized.

Animals↗
PubMed1980

Optically active derivatives of imidazolines. alpha-Adrenergic blocking properties.

The synthesis and alpha-adrenergic blocking activity of a series of optically active 2,4-disubstituted imidazolines are presented. The substituted analogues of naphazoline, tolazoline, and clonidine possess moderate alpha-adrenergic blocking activity with -log KB values in the range from 4.77 to 6.57. The differences between the alpha-adrenergic blocking activity of the stereoisomers of the 2,4-disubstituted imidazolines were small or insignificant in the rabbit aortic tissue preparations.

Adrenergic alpha-Antagonists↗
PubMed1980

Isolation and characterization of alkali-labile oligosaccharide units from horse glycophorin.

The O-glycosidically linked carbohydrate units of glycophorin derived from horse erythrocyte membrane were released as reduced oligosaccharides by alkaline borohydride treatment. One tetrasaccharide, two trisaccharides, and two disaccharides were purified by gel filtration and ion-exchange chromatography. Studies employing periodate oxidation, methylation analysis and gas-liquid chromatography-mass spectrometry revealed the following structures for these oligosaccharides; a tetrasaccharide; N-glycolylneuraminyl-(2 leads to 3)-D-galactopyranosyl-(1 leads to 3)-[N-glycolylneuraminyl-(2 leads to 6)]-D-N-acetylgalactosaminitol, trisaccharides; N-glycolylneuraminyl-(2 leads to 3)-D-galactopyranosyl-(1 leads to 3)-D-N-acetylgalactosaminitol and D-galactopyranosyl-(1 leads to 3)-[N-glycolylneuraminyl-(2 leads to 6)-a1-D-N-acetylgalactosaminitol, disaccharides; D-galactopyranosyl-(1 leads to 3)-D-N-acetylgalactosaminitol and N-glycolylneuraminyl-(2 leads to 3)-D-galacitol.

Alkalies↗
PubMed1980

Amino acid sequence and attachment sites of oligosaccharide units of porcine erythrocyte glycophorin.

The amino acid sequence of the glycophorin from porcine erythrocyte membrane has been determined by Edman degradation. Porcine glycophorin is a polypeptide chain of 133 amino acid residues and contains 12 oligosaccharide units attached to the amino-terminal side of the molecule. Ten oligosaccharides are linked O-glycosidically to threonine/serine residues and the remaining two oligosaccharides are attached N-glycosidically to asparagine residues. The amino acid sequence is consistent with the transmembrane orientation of glycophorin. Porcine and human glycophorins are similar in amphiphilic property, molecular size, and carbohydrate content, but the two glycophorins differ considerably in the amino acid sequence: particularly, the amino-terminal sequences which are highly glycosylated show no homology.

Amino Acid Sequence↗
PubMed1979

Partial amino acid sequence of glycophorin from porcine erythrocyte membranes.

Glycophorin from porcine erythrocyte membranes was digested with trypsin and chymotrypsin. Some of the peptides were isolated by conventional techniques. The amino acid sequence was determined for two isolated peptides: a chymotryptic glycopeptide of 19 residues and a tryptic peptide of 36 residues which represented the carboxy terminal of the glycophorin.

Amino Acid Sequence↗
PubMed1978

3-O-Methyl galactose found in polysaccharides of Lampteromyces japonicus.

A polysaccharide fraction from Lampteromyces japonicus contained a sugar (4%), which was identified as 3-O-methyl galactose by demethylation with boron trichloride, periodate oxidation of the methyl glycoside derivative and gas chromatography-mass spectrometry of the alditol acetate derivative.

Chromatography, Gas↗
PubMed1978

Purification and chemical characterization of polysaccharides obtained from Lampteromyces japonicus by concanavalin A-sepharose affinity chromatography.

Two classes of neutral polysaccharide which could not be separated from each other by conventional methods were isolated from the fungus, Lampteromyces japonicus, by affinity chromatography using concanavalin A-Sepharose. The polysaccharide retained on the concanavalin A-Sepharose column was eluted with 0.05 M methyl alpha-D-mannopyranoside and appeared to be alpha-mannan, while that which passed through the column was virtually all beta-glucan. Both polysaccharides were subjected to Smith-type degradation, methylation, acetolysis and glucosidase treatment. The results indicated that the alpha-mannan contained predominantly alpha-(1 leads to 2)-linked side chains branching from an alpha-(1 leads to 6)-linked backbone at the (1 leads to 2,6)-linked mannopyranosyl residues. Galactose was attached to approximately one-quarter of the non-reducing mannose terminals. The beta-glucan seemed to contain mainly (1 leads to 6)-linked side chains branching from a (1 leads to 3)-linked backbone at the (1 leads to 3,6)-linked glucopyranosyl residues.

Agaricales↗