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D B Hope

Publications and source records attributed to D B Hope.

65 records · Page 4Linked to original sources
PubMed1967

The oxidation of lysine and oxalysine by Mytilus edulis: Identification of the products formed in the presence and the absence of catalase.

1. O-(2-Aminoethyl)serine (oxalysine) was shown to be a substrate of the l-amino acid oxidase of the digestive gland of the common mussel, Mytilus edulis. 2. Three atoms of oxygen were consumed per mole of oxalysine oxidized in the presence of catalase; l-lysine under the same conditions consumed only one atom. 3. The products of oxidation of oxalysine in the presence and the absence of catalase were: ethanolamine, N-oxalylethanolamine and 3-morpholone (the oxygen analogue of 2-piperidone). After acid hydrolysis 70% of the oxalysine oxidized was recovered as ethanolamine. 4. In the absence of catalase 2-aminoethoxyacetic acid was also detected. 5. The products identified account quantitatively for the oxalysine oxidized and for the oxygen uptake. 6. N-Oxalylethanolamine and 2-aminoethoxyacetic acid have been synthesized. 7. Treatment of extracts of the digestive gland at pH3.0 completely inactivated the catalase, leaving the l-amino acid oxidase unaffected. 8. The major product of the oxidation of lysine in the absence of catalase was 2-piperidone.

Journal Article↗
PubMed1967

Fractionation of neurophysin by molecular-sieve and ion-exchange chromatography.

Neurophysin has been separated into seven distinct protein fractions. One of these components had no hormone-binding activity. The fractions that had hormone-binding activity were similar in amino acid composition: their cystine content was in the range 11.5-14.5%. The major component, neurophysin-M, was distinguished from the protein isolated by van Dyke by the presence of methionine and the absence of histidine. Neurophysin-M binds both oxytocin and vasopressin with similar affinities.

Amino Acids↗
PubMed1967

The isolation of purified neurosecretory granules from bovine pituitary posterior lobes. Comparison of granule protein constituents with those of neurophysin.

1. A procedure for the isolation of highly purified neurosecretory granules from the posterior lobe of the bovine pituitary gland is described. The preparation was free from contamination by the mitochondrial enzyme succinate dehydrogenase and the lysosomal enzyme cathepsin. 2. The biological activities of the neurosecretory granules were measured: the oxytocic activity was 11.61+/-1.30units and the pressor activity was 10.73+/-1.74units/mg. of protein. 3. A lysate of the isolated granules was shown to contain two proteins that appear to be identical with two of the constituents of neurophysin. 4. The constituents of neurophysin not present in neurosecretory granules could not be detected in any other subcellular fraction. It is suggested that the components of neurophysin not present in the neurosecretory granules arise as a result of the degradation of the two granular proteins.

Animals↗
PubMed1967

The dimerization of delta-1-piperidine-2-carboxylic acid.

The l-amino acid oxidase of Mytilus edulis has been used to oxidize l-lysine on a large scale in the presence of catalase. The alpha-oxo acid derived from lysine cyclizes to a Schiff base, which readily dimerizes. The dimer undergoes spontaneous dehydration and decarboxylation to form 1,2,3,4,5,6,7,8-octahydropyrido[3,2-a]-indolizin-10(4bH)-one. This structure was established by a study of its molecular weight and infrared, nuclear-magnetic-resonance and mass spectra.

Amino Acid Oxidoreductases↗
PubMed1967

The composition of crystalline complexes of neurophysin-M with [8-arginine]-vasopressin and oxytocin.

Neurophysin-M, a methionine-containing protein that is the major constituent of neurophysin, has been crystallized as complexes with [8-arginine]-vasopressin. Three moles of vasopressin alone or 2 moles of vasopressin together with 1 mole of oxytocin are bound/mole of protein. An amorphous complex of the protein with oxytocin alone contains 2 moles of the hormone/mole of protein. Deamino-[8-arginine]-vasopressin, a highly active basic analogue of vasopressin, is not bound by neurophysin. The primary amino group of both vasopressin and oxytocin is necessary for binding with neurophysin.

Journal Article↗