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Biomedical subjects

H R Morris

Publications and source records attributed to H R Morris.

At least 235 records · Page 13Linked to original sources
PubMed1981

Extended performance using a high field magnet mass spectrometer.

The development of a high field magnet for high mass electron impact, chemical ionization, field desorption and fast atom bombardment mass spectrometric studies is described. Its utility is illustrated with examples from structural studies of vitamin B12 biosynthetic intermediates, oligosaccharides, glycopeptides and the bleomycin antibiotics. The technique has also greatly assisted sequence studies of protein derived peptides.

Bleomycin↗
PubMed1980

Biomolecular structure determination by mass spectrometry.

Mass spectometry, conventionally used with smallish molecules (less than 1,000 daltons), has suprisingly emerged as a powerful technique for the determination of the amino acid sequences of proteins and the structure of glycopeptides as well as for the characterization of biologically active materials of unusual structure such as the peptidolipids. Further applications to biomedical problems are foreseen.

Amino Acid Sequence↗
PubMed1980

Characterisation of an adrenal zona glomerulosa-stimulating component of posterior pituitary extracts as alpha-MSH.

The secretion of aldosterone from the zona glomerulosa of the mammalian adrenal cortex is stimulated by ACTH, potassium, angiotensin II and III, growth hormone, serotonin and E series prostaglandins. Some experimental and clinical studies suggest that additional stimulants of the zona glomerulosa must exist, possibly including pituitary factors other than ACTH. The possibility that posterior pituitary extracts may contain a zona glomerulosa stimulant was first suggested 20 years ago, but has since received little attention. We describe here the purification from posterior pituitary extracts of activities that stimulate rat glomerulosa cells and whole tissue in vitro. One of the active compounds has been identified as alpha-MSH (melanocyte stimulating hormone).

18-Hydroxydesoxycorticosterone↗
PubMed1980

Slow-reacting substances and their structural elucidation.

For more than forty years since their discovery, the structure of a group of closely related materials known collectively as slow-reacting substances has been unknown. These substances are released from a variety of tissues in response to immunological or non-immunological stimulation. A slow-reacting substance is believed to be implicated in hypersensitivity reactions such as asthma; in order to fully understand its bronchoconstrictor role, the structural elucidation of these materials has been a necessary (albeit difficult) task. Studies on both immunologically generated slow-reacting substance of anaphylaxis (SRS-A) and other slow-reacting substances (SRSs) have indicated a precursor role for arachidonic acid in their biosynthesis; this, coupled with enzymic and chemical activity destruction data, gave an insight into the structure of these moieties. In order to define the structure of these materials homogeneous SRS-A was required; a purification scheme was developed relying on the high resolution separative capability of reverse-phase high pressure liquid chromatography, resulting in extensively purified SRS-A. It was then possible to demonstrate that SRS-A possessed a characteristic ultraviolet spectrum, allowing us for the first time to define a major structural moiety in the molecule (conjugated triene). To complement studies on, and to act as a model for the more pathologically relevant SRS-A, a slow-reacting substance was produced from rat basophilic leukaemia (RBL-1) cells. The structure of this biologically active species has been determined by mass spectrometric examination of the intact molecule as a derivative, together with analytical protein chemical studies, and shown to be the novel peptidolipid 5-hydroxy-6-cysteinylglycinyl-7,9,11,14-eicosatetraenoic acid.

Animals↗
PubMed1980

Slow-reacting substances and their formation by a lipoxygenase pathway.

Slow-reacting substances are formed from arachidonic acid by the action of a lipoxygenase, which leads to the formation of 5-hydroperoxy, 6, 8, 11, 14 eicosatetraenoic acid. The covalent structures of SRS-A from guinea-pig lung and SRS from RBL-1 cells have been determined by protein chemical analysis and electron impact mass spectrometry of a derivative of the intact molecules. The structures of SRS-A and SRS are identical, being 5-hydroxy-6-cysteinyl-glycinyl-7, 9, 11, 14-eicosatetraenoic acid. SRSs may be formed by a combination of the metabolism of arachidonic acid by the lipoxygenase pathway and the glutathione detoxification pathway involving nucleophilic attack on 5,6-oxidoeicosatetraenoic acid.

Amino Acids↗
PubMed1980

Slow reacting substances (SRSs): the structure identification of SRSs from rat basophil leukaemia (RBL-1) cells.

Slow Reacting Substances have been produced from RBL-l cells by calcium ionophore A23187 and purified to homogeneity by high pressure liquid chromatography (HPLC). The structure of the major biologically active species has been determined by mass spectrometric examination of the intact molecule as a derivative, together with amino-acid analysis and sequence determination. The characteristic triene chromophore which we originally identified in immunologically generated SRS-A is present in RBL-l SRS, and we determine the structure of this SRS as the thio-substituted dipeptide, 5-hydroxy-6-cysteinylglycinyl-7,9,11,14-eicosatetraenoic acid.

Amino Acid Sequence↗