Isolation and identification of a fucose-containing ganglioside from bovine thyroid gland

Bovine thyroid glands are known to contain a complex array of gangliosides. One of the predominant gangliosides was isolated and analyzed by gas-liquid chromatography and mass spectrometry. The carbohydrate composition was fucose, N-acetylneuraminic acid, galactose, N-acetylgalactosamine, and glucose in molar ratios of 1:1:2:1:1. The structure of the ganglioside was identified as:

     

Isolation and identification of polyprenols from bovine thyroid gland.

The presence of polyprenols in bovine thyroid was demonstrated. After preparative isolation, the structure was elucidated by chemical and spectroscopic techniques. The main polyprenol homologue has a molecular weight of 1380 corresponding to the presence of 20 isoprene units. From NMR studies it appears that 18 units have the cis configuration and that the 2 others are trans isoprene units. The dolichol content amounts to 0.2 mg/g wet weight. About 5% was found in the esterified form.     

Isolation and identification of vasopressin- and oxytocin-immunoreactive substances from bovine pineal gland. Presence of N alpha-acetyloxytocin

Peptides with vasopressin- and oxytocin-immunoreactivity were purified from bovine pineal glands. Three immunoreactive peptides were purified by successive high performance liquid chromatography steps in sufficient quantities for identification by fast atom bombardment-mass spectrometry. Two peptides were characterized as authentic vasopressin and oxytocin. Their identities were in agreement with the observed immunoreactivities, high performance liquid chromatography behavior, and biological activity. The third peptide was identified as N alpha-acetyloxytocin. The presence of the acetyl group was demonstrated by the molecular mass of the peptide, and the N alpha position was shown to be the modified site by the presence of a blocked NH2 terminus. N alpha-Acetylation of oxytocin may be involved in altering the biological properties of the peptide.     

Isolation of a new ligand-carrying casein fragment from bovine mammary gland microsomes.

Whilst looking for components involved in retinol metabolism in secreting mammary gland cells, a 12 kDa protein was isolated. This protein had bound a ligand with characteristics of retinol. N-Terminal sequencing and amino acid analysis showed that this protein is highly homologous with an alpha-s1-casein fragment. No ligand was found for beta-lactoglobulin, previously thought to be involved in retinol metabolism.     

Isolation of an activator for prostaglandin hydroperoxidase from bovine vesicular gland cytosol and its identification as uric acid.

The enzymatic conversion of prostaglandin G₁ to H₁ was stimulated by an activator present in the cytosol of bovine vesicular gland. The activator was purified by Sephadex G-25 gel filtration and Dowex 1 column chromatography. The purified activator was identified to be uric acid by thin layer chromatography, ultraviolet and infrared absorption spectroscopy and combined gas chromatography-mass spectroscopy. Among various purine compounds tested, only uric acid and 2,8-dihydroxyadenine were active.     

Determination in situ of neutral and acidic fucose-containing oligosaccharides in the bovine submandibular gland

Lectins conjugated to horseradish peroxidase in combination with selected exoglycosidase digestion procedures were used to localize fucoglycoconjugates in the bovine submandibular gland. In particular, sequential treatments were employed to determine the distribution of neutral and acidic fucose-containing oligosaccharides that were previously shown to be present by biochemical techniques. Information was obtained on the distribution of the acidic oligosaccharide A-1a, -Fuc(12)--Gal-(14)--GlcNAc-(13)-[-NeuAc-(26)]-GalNAc-ol, which was sequenced in situ and localized in acinar cells.     

Metabolism of D-mannosamine in bovine thyroid gland slices.

1. The nature of the acid-soluble mannosamine intermediates was investigated in bovine thyroid gland slices after incubation with a tracer amount of [14C]mannosamine plus 10 mM carrier mannosamine. 2. These radioactive intermediates were separated by ion exchange, columns, characterized by paper chromatography and were identified as N-acetylmannosamine-6-P. The radioactivity associated with these acid-soluble compounds constituted about 17 percent of the added [14C]mannosamine. 3. [14C]Mannosamine was incorporated as sialic acid only into thyroglobulin.     

Isolation and characterization of a ganglioside containing fucose from boar testis.

A ganglioside containing fucose (fucoganglioside) was obtained from boar testis and purified by silicic acid and DEAE-cellulose column chromatographies and preparative thin layer chromatography. The structure of this ganglioside, determined by chemical and enzymatic methods was: (see article). Its fatty acids were mainly long chain saturated ones (20 : 0, 22 : 0, 24 : 0). Its long chain bases consisted of 27% C(16:1) sphingosine and 68% C(18:1) sphingosine.     

Isolation and characterization of plasma membrane from lactating bovine mammary gland

Plasma membranes were isolated from lactating bovine mammary gland. Two crude membrane fractions; medium/d 1.033 (light membrane) and 1.033/1.053 interfaces (heavy membrane), were obtained by Ficoll density gradient centrifugation of osmotically washed microsomal fraction. Two crude membranes were further purified separately by sucrose density gradient centrifugation. Both light and heavy membranes banded at a sucrose density of 1.14. The purified membranes appeared as heterogeneous smooth membrane vesicles on electron microscopy. The contaminating suborganelles were not detected. The yield of the purified membranes relative to the homogenate was 1.2%. The degree of purity of the membranes was shown by a great increase in the specific activity of 5′-nucleotidase over the homogenate of 20-fold for light membrane and of 16-fold for heavy membrane. The relative activities of Mg²⁺-ATPase, (Na⁺ + K⁺)-ATPase, γ-glutamyl transpeptidase, phosphodiesterase I, akaline phosphatase and xanthine oxidase were also high (12–18-times) and nearly 20% of these enzymes was recovered. The activity of marker enzyme for mitochondria, endoplasmic reticulum and Golgi apparatus was very low, while that of acid phosphatase for lysosome was relatively high (5-times). DNA and RNA contents were very low. The major polypeptides rich in other suborganelles were not detected profoundly in the membrane fraction and the polypeptide compositions in both light and heavy membranes were similar upon SDS-polyacrylamide gel electrophoresis.     

Alpha-fucosidase-ganglioside interactions. Action of alpha-L-fucosidase from the hepatopancreas of Octopus vulgaris on a fucose-containing ganglioside (Fuc-GM1).

alpha-L-Fucosidase, prepared in highly purified form (Mr 70 000-74 000) from Octopus hepatopancreas, was able to hydrolyse a fucose-containing ganglioside, namely Fuc-GM1 (II3NeuAc,IV2Fuc-GgOse4-Cer). The enzyme showed an irregular kinetic behaviour (v/[S] and v/[E] relationships following sigmoidal curves) when working on micellar Fuc-GM1 (Mr of the micelle 500 000), but obeyed regular hyperbolic kinetics when acting on low-Mr substances. It was observed that, on incubation with micellar Fuc-GM1 under the conditions used for the enzyme assay, Octopus alpha-L-fucosidase produced a ganglioside-enzyme complex that was catalytically inactive. This complex had an Mr exceeding 500 000 and a ganglioside/protein ratio of 4:1 (w/w), which is consistent with a stoichiometric combination of one ganglioside micelle with two enzyme molecules. Inactivation of alpha-L-fucosidase by formation of the corresponding complexes was also obtained with micellar gangliosides GM1 (II3NeuAc-GgOse4-Cer), GD1a (II3NeuAc,IV3NeuAc-GgOse4-Cer) and GT1b [II3(NeuAc)2,IV3-NeuAc-GgOse4-Cer], which are not substrates for the enzyme, indicating that the ganglioside micelles per se act as enzyme inhibitors. However, alpha-L-fucosidase easily forms a Fuc-GM1-alpha-L-fucosidase complex, displaying regular Michaelis-Menten kinetics. Therefore the anomalous behaviour exhibited by alpha-L-fucosidase on micellar Fuc-GM1 is likely due to formation of the complex, which separates the fucosyl linkage from the active site of the complexed enzyme, but makes it available to the enzyme in the free form.     

Isolation and structure identification of a morphine-like peptide enkephalin in bovine brain.

The ability of bovine brain extracts to compete in a selective fashion for opiate receptor binding is attributable to a small peptide. The substance has been purified to homogeneity and identified as comprising two penta-peptides HTyrGlyGlyPheLeuOH (Leucine-enkephalin) and HTyrGlyGlyPheMetOH (methionine enkephalin). Bovine brain contains 4 times as much leucine-enkephalin as methionine-enkephalin in contrast to pig brain in which these ratios are reversed. Competition for opiate receptor binding by leucine-enkephalin is reduced more by sodium and enhanced more by manganese than is the case for methionine-enkephalin, suggesting that leucine-enkephalin may be a “purer” agonist than methionine-enkephalin.     

Isolation and identification of a small molecular weight inhibitor of cyclic nucleotide phosphodiesterase from bovine brain.

In a search for endogenous regulators for cyclic nucleotide phosphodiesterase (3':5'-cyclic-AMP 5'-nucleotidohydrolase, EC 3.1.4.17), we found that the ultrafiltrate of bovine brain homogenate contained a cyclic nucleotide phosphodiesterase inhibitor. The inhibitor-containing fraction was further purified by ion-exchange column chromatography and gel filtration chromatography. The purified inhibitor was found to be a small molecular weight compound which had a maximum absorption at 248 nm. This compound was identified by thin-layer chromatography and high-pressure liquid chromatography as hypoxanthine. We suggest that hypoxanthine may serve as an endogenous regulator for the hydrolysis of cyclic nucleotide by cyclic nucleotide phosphodiesterase.     

Isolation and identification of cholesteryl alkyl ethers from bovine cardiac muscle

Cholesteryl alkyl ethers have been isolated from bovine cardiac muscle and characterized by thin-layer and gas-liquid chromatography. The fraction contained at least three homologues. Cholesteryl hexadecyl ether, which accounted for over 90% of the total components observed on gas chromatography, was identified by mass spectrometry.