Biochimica et Biophysica Acta (BBA) - Specialized Section on Mucoproteins and Mucopolysaccharides最新文献

• 1.

  1. Immunochemical methods were used to study the homogeneity and immunological relationships of bovine submaxillary mucin preparations isolated according to the methods described by Gottschalk¹ and by Pigman² and their collaborators and disgnated BSM-G (“described by Gottschalk” and BSM-G (“described by Pigman”), respectively.

• 2.

  2. Antisera suitable for immunodiffusion and immunoelectrophoresis were obtained after intravenous and subcutaneous (with Freunds's adjuvant) injections into rabbits of submaxillary gland extracts and mucins. Antibodies directed against the principal mucin components were produced after injection of BSM-P; this was demonstrated by the quantitative precipitation of sialic acid upon addition of BSM-P to anti-BSM-P.

• 3.

  3. Neither BSM-G nor BSM-P were homogenous by precipitin-curve analysis. Immunoelectrophoresis showed that BSM-G preparations contained from four to nine components, three of which were glycoproteins. BSM-P did not contain extraneous proteins, but it consisted of at least two glycoproteins. Two of the glycoproteins in BSM-G formed confluent arcs with BSM-P.

• 4.

  4. Further fractionation² BSM-G afforded a fraction which was indistinguishable from BSM-P and which corresponds to approx. 60% of the dry weight of BSM-G.

Glycosaminoglycans were isolated from beef cornea and further fractionated on the basis of ethanol solubility. Variability of keratan sulfate was found. The forms differ in reducing activity, sulfur content, infrared spectra and specific optical rotation. Keratan sulfotransferase (3′-phosphoadenylylsulfate: keratan sulfotransferase) activity is low but detectable in beef cornea-epithelial extract. Keratan sulfate with the lower sulfate content acts as a sulfate acceptor while the other does not.

The isolation of the cell walls of three mycobacterial strains is described and their chemical compositions have been determined. The cell-wall preparations were purified by treatment with trypsin (EC 3.4.4.4), chymotrypsin (EC 3.4.4.5) and pepsin (EC 3.4.4.1). Digestion with lysozymes (EC 3.2.1.17) from hen's egg-white, duck's egg-white and human milk resulted in the liberation of substances which reacted with reagents specific for amino sugars.

• 1.

  1. l-Glutamine-d-fructose 6-phosphate aminotransferase (EC 2.6.1.16) has been isolated from liquid nitrogen-powdered aortic and pulmonary-valves of calves and cows.

• 2.

  2. Young valves show greater enzymatic activity than older, while, in calves, the aortic-valve aminotransferase is more active than the pulmonary-valve enzyme.

• 3.

  3. Sodium salicylate produces a marked inhibition of the aortic and pulmonary-valve aminotransferase, while its isomer, p-hydroxybenzoic acid has a much less inhibitory effect. Chloroquine diphosphate causes a marked inhibition only at high concentration.

• 4.

  4. The aortic and pulmonary-valve 3′-phosphoadenosine-5′-phosphosulphate-synthesizing systems have been isolated and have been found to be unaffected by the drugs studied.

• 5.

  5. The possibility of the enzymatic synthesis of glucosamine 6-phosphate being one control point for the action of some anti-inflammatory drugs is discussed.

• 1.

  1. The presence of blood-group-substance activity in bovine saliva prompted investigation of the immunologic behavior of bovine submaxillary mucin and of glycopeptides obtained by proteolytic digestion of the mucin.

• 2.

  2. Purified preparations of bovine submaxillary mucin inhibited hemolysis in the bovine J-anti-J system. Removal of sialic acid from the mucin by mild acid hydrolysis increased the potency of the preparation. Periodate oxidation of sialic acid free-bovine submaxillary mucin destroyed the blood-group J activity.

• 3.

  3. Bovine submaxillary mucin exhibited a high degree of specificity. it did not inhibit other bovine blood group systems, and it was inactive in human B, M, N and I, i systems; bovine submaxillary mucin had moderate inhibition in the A and O (H) systems.

• 4.

  4. Bovine submaxillary mucin was digested by pronase and papain (EC 3.4.4.10), and the glycopeptides were fractionated through Sephadex G-50. Glycopeptide fractions which contained the greatest amounts of hexosamine, galactose, and fucose relative to sialic acid were the best glycopeptide inhibitors of J hemolysis.

• 5.

  5. Bovine submaxillary mucin cross-reacted with antiserum to Type XIV pneumococcal polysaccharide only after removal of sialic acid from the mucin. Possibly some d-galactosyl residues were exposed by the removal of sialic acid from bovine submaxillary mucin.

A sialic acid-free glycopeptide preparation was isolated from a proteolytic digest of α₁-glycoprotein (pleuromucoid). By paper electrophoresis at pH 6.4, this fraction showed four zones of same carbohydrate composition but of different amino acid composition and sequence.

This preparation was submitted to digestion with response, resulting in the release of some free or combined amino acids. After purification by gel filtration on Sephadex G 25, a new glycopeptide was obtained; only a limited number of amino acids were present: aspartic and glutamic acids, threonine, proline, glycine and lysine. By paper electrophoresis at pH 6.4, three zones were identified; their amino acid composition and sequence were determined.

The structure of the three glycopeptide was found different. Similar results were obtained with orosomucoid.

The present evidence suggests that the diverse glycopeptide chains of the α₁-glycopeptide don't have all the same consitutition.

Following the intravenous administration of Na₂⁷⁵SeO₄ and Na₂³⁵SO₄ in rabbits, the non-dialyzable solids of urine were labelled with ³⁵S and ⁷⁵Se in a parallel manner both on BaCO₃-fractionated specimens and when chondroitin sulfate A and C were isolated by glass-paper chromatography. ⁷⁵Se-labelled selenate may be a useful adjunct to the tools currently available for the metabolic studies of sulfomucopolysaccharides.