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A Boersma

Publications and source records attributed to A Boersma.

At least 55 records · Page 3Linked to original sources
PubMed1984

Further characterization, by a combined high-performance liquid chromatography/1H-NMR approach, of the heterogeneity displayed by the neutral carbohydrate chains of human bronchial mucins.

From bronchial mucins of cystic fibrosis patients with blood group O, the carbohydrate chains were released in the form of oligosaccharide-alditols by alkaline borohydride treatment. Application of high-performance liquid chromatography directly on the pool of neutral oligosaccharides afforded 23 fractions. Twenty oligosaccharide structures were characterized by employing 500-MHz 1H-NMR spectroscopy in conjunction with sugar analysis. Thirteen among these had been revealed before to occur in human bronchial mucins [Van Halbeek, H., Dorland, L., Vliegenthart, J. F. G., Hull, W. E., Lamblin, G., Lhermitte, M., Boersma, A., and Roussel, P. (1982) Eur. J. Biochem. 127, 7-20], when paper-chromatographic fractionation of this pool of neutral oligosaccharides was employed. High-performance liquid chromatography enabled to obtain another seven pentasaccharide and hexasaccharide alditols; the largest-size representatives are: (Formula see text). Thereby, this approach afforded deeper insight into the structural heterogeneity displayed by the carbohydrate chains of bronchial mucins.

Bronchi↗
PubMed1984

Primary structure determination of five sialylated oligosaccharides derived from bronchial mucus glycoproteins of patients suffering from cystic fibrosis. The occurrence of the NeuAc alpha(2----3)Gal beta(1----4)[Fuc alpha(1----3)] GlcNAc beta(1----.) structural element revealed by 500-MHz 1H NMR spectroscopy.

The structure of sialylated carbohydrate units of bronchial mucins obtained from cystic fibrosis patients was investigated by 500-MHz 1H NMR spectroscopy in conjunction with sugar analysis. After subjecting the mucins to alkaline borohydride degradation, sialylated oligosaccharide-alditols were isolated by anion-exchange chromatography and fractionated by high performance liquid chromatography. Five compounds could be obtained in a rather pure state; their structures were established as the following: A-1, NeuAc alpha(2----3)Gal beta(1----4) [Fuc alpha(1----3)]GlcNAc beta(1----3)Gal-NAc-ol; A-2, NeuAc alpha(2----3)Gal beta(1----4)GlcNAc beta(1----6)-[GlcNAc beta (1----3)]GalNAc-o1; A-3, NeuAc alpha(2----3)Gal beta-(1----4)[Fuc alpha(1----3)]GlcNAc beta(1----3)Gal beta(1----3) GalNAc-o1; A-4, NeuAc alpha(2----3)Gal beta(1----4)[Fuc alpha(1----3)]Glc-NAc NAc beta(1----6)[GlcNAc beta(1----3)]GalNAc-o1; A-6,NeuAc alpha-(2----3) Gal beta(1----4)[Fuc alpha(1----3)]GlcNAc beta(1----6)[Gal beta-(1----4) GlcNAc beta(1----3)]GalNAc-o1. The simultaneous presence of sialic acid in alpha(2----3)-linkage to Gal and fucose in alpha(1----3)-linkage to GlcNAc of the same N-acetyllactosamine unit could be adequately proved by high resolution 1H NMR spectroscopy. This sequence constitutes a novel structural element for mucins.

Bronchi↗
PubMed1983

Structural studies of the carbohydrate component of a human, parotid-saliva, proline-rich glycoprotein.

The carbohydrate chains of the human, parotid-saliva, proline-rich glycoprotein were released as oligosaccharides by hydrazinolysis and were fractionated by high-pressure-liquid chromatography. Four oligosaccharides were characterized. On the basis of compositional analysis, sequential enzymic degradation, and methylation data, the carbohydrate moiety of the glycoprotein was found to be a complex-type oligosaccharide containing a tri-D-mannosyl-di-N-acetylchitobiose core with two and three lactosamine branches, and an L-fucosyl group linked to O-6 of the asparagine-linked 2-acetamido-2-deoxy-D-glucose residue. In addition, several L-fucosyl groups, linked at O-6 of the penultimate D-galactose residues, are present in variable proportions. The biological significance of these results is discussed.

Carbohydrates↗
PubMed1983

Enzymatic cleavage of pyroglutamyl-histidyl-dopamine, a TRH-related pseudo-peptide by porcine serum and brain hoimogenate.

The Pseudo-peptide (pGlu-His-Dopamine) was subjected to enzymatic degradation by porcine serum and brain homogenate. The digests were quantitatively analyzed by HPLC to provide evidence for liberation of pyroglutamic acid and dopamine in serum and of pyroglutamic acid in brain. The yield of liberation of pGlu is about 3% in serum digests and about 0.70% in brain digests after 3 minutes incubation. The time course of the yield of liberation of both pGlu and dopamine in serum digests is determined. The "stability in vitro" toward enzymes of serum and brain homogenate of a new type of drug based on the combination of peptidic fragment of TRH-(Thyrotropin-Releasing Hormone:pGlu-His-Pro-NH2) with a non peptide moiety (dopamine) is considered and discussed.

Animals↗
PubMed1982

Circular dichroism studies on the proline-rich glycoprotein of human parotid saliva.

Previous results on the primary structure of the human parotid saliva proline-rich glycoprotein established the concept of repetitive domains in the sequence of that glycoprotein, tryptic glycopeptides of proline-rich glycoprotein representing the basic structure. The present work is concerned with the study of the secondary structure of the proline-rich glycoprotein, and of tryptic glycopeptides with and without the glycan moiety, using circular dichroism. CD spectra exhibit the same secondary structure with about 60% of polyproline II helical structure for the proline-rich glycoprotein, tryptic glycopeptides and their deglycosylated homologues. The present results are in fair agreement with the amino acid sequence results and suggest a model for the schematic representation of the proline-rich glycoprotein.

Calcium↗
PubMed1982

Primary-structure determination of fourteen neutral oligosaccharides derived from bronchial-mucus glycoproteins of patients suffering from cystic fibrosis, employing 500-MHz 1H-NMR spectroscopy.

The structure of carbohydrate units of bronchial-mucus glycoproteins obtained from cystic fibrosis patients was investigated by 500-MHz 1H-NMR spectroscopy and methylation analysis. To that purpose, the mucin was subjected to alkaline borohydride degradation. Neutral oligosaccharide-alditols, ranging in size from disaccharides to pentasaccharides, were isolated. Eight compounds could be purified to homogeneity; furthermore, three fractions were obtained consisting mainly of two components. For all 14 compounds the primary structure could be elucidated. 500-MHz 1H-NMR spectroscopy was found to be effective in detecting heterogeneity and to be invaluable for the determination of structures in mixtures of oligosaccharide-alditols. The structures can be divided into two groups depending on the core disaccharide. One group contains Gal(beta 1 leads to 3)GalNAc-ol as common structural element, the other GlcNAc(beta 1 leads to 3)GalNAc-ol. Both disaccharides were identified as such; the other compounds can be conceived as extensions thereof. The most complex representatives of the two groups are: (formula; see text) The italicized structural elements, comprising the SSEA-1 determinant and the type-1 blood-group-H determinant, are novel sequences in oligosaccharide chains of mucin-type glycoproteins.

Chemical Phenomena↗
PubMed1981

Evidence for the presence of the trimannosyl-di-N-acetylchitobiose core in the carbohydrate chains of human-parotid, proline-rich glycoprotein.

The carbohydrate chains of the human-parotid, proline-rich glycoprotein are linked through a single type of carbohydrate-peptide linkage (asparaginyl-N-acetylglucosamine). The structure of the internal part of the carbohydrate chains, determined by chemical, enzymic, and g.l.c.--m.s. methods, includes the trimannosyl-di-N-acetylchitobiose core involved in the carbohydrate-peptide linkage. Furthermore, an L-fucose residue is linked to the 2-acetamido-2-deoxy-D-glucosyl residue linked to the L-asparaginyl residue. The sequence of the peripheral part of the chains has also been determined as alpha-L-Fuc rho leads to beta-D-Gal rho leads to beta-D-Glc rho NAc leads to alpha-D-Man rho, suggesting a double-branched, basic carbohydrate structure.

Glucans↗
PubMed1980

Oligosaccharides of human bronchial glycoproteins. Neutral di- and trisaccharides isolated from a patient suffering from chronic bronchitis.

Human bronchial glycoproteins from a patient suffering from chronic bronchitis were subjected to alkaline borohydride degradation and a heterogeneous mixture of reduced oligosaccharides and glycopeptides was obtained. The shortest neutral oligosaccharides were subsequently fractionated by DAX4 anion exchange chromatography into 12 fractions. Five major oligosaccharides were purified by preparative paper chromatography. Their structures were determined by using periodic oxidation, methylation analysis, gas liquid chromatography-mass spectrometry, and enzymatic degradation. Two oligosaccharides and three trisaccharides were characterized as galactose (Gal) beta 1 leads to 3 N-acetylgalactosaminitol (GalNActitol), N-acetylglucosamine (GlcNAc) beta 1 leads to 3 GalNActitol, Gal 1 leads to 4 GlcNAc 1 leads to 3 GalNActitol, GlcNAc 1 leads to 3 Gal 1 leads to 3 GalNActitol and fucose alpha 1 leads to 2 Gal beta 1 leads to 3 GalNActitol.

Bronchi↗
PubMed1978

[Biochemical study of the glycosaminoglycan peptides obtained from osteoarthrotic and normal femoral heads (author's transl)].

Glycosaminoglycan peptides prepared by papain hydrolysis of different regions were obtained from osteoarthrotic and normal human femoral heads. Data obtained in these experiments show that in osteoarthrosis a decrease in keratan sulfate and an increase in chondroitin sulfate are observed. Since keratan sulfate appeared to play an important role in proteoglycan aggregation, we suggest that the keratan sulfate decrease is one of the factors involved in the cartilage disorder observed in patients suffering from osteoarthrosis.

Aged↗
PubMed1975

[Endo beta-N-acetylglucosaminidase in human liver].

Endo beta-N-acetylglucosaminidase activity was found in a alpha-L-fucosidase preparation purified from human liver homogenates, using glycopeptides from human parotid glycoprotein as a substrate. An oligosaccharide was purified and after reduction N-acetylglucosaminitol was shown by paper chromatography. Thus, the specificity and the significance of this endoglycosidase in glycoprotein catabolism are discussed.

Acetylglucosamine↗
PubMed1975

[Report on the study of hyaluronic acid in the diagnosis of pleural mesotheliomas: study of 100 hyaluronic acid rich effusions].

Hyaluronic acid was measured in 1580 pleural effusions. We report 100 cases of hyaluronate-rich pleural fluids. Correlations betueen clinical, radiological and histological diagnosis of mesothelioma and the characterization of hyaluronate are discussed. These data suggest the possibility of a biochemical approach for the diagnosis of pleural malignant tumours.

Asbestosis↗