Biomedical subjects

I Miki

Publications and source records attributed to I Miki.

43 records · Page 3Linked to original sources

PubMed1989

11,12-leukotriene A4: synthesis and metabolism.

11(S),12(S)-oxido-5Z,7E,9E,14Z-eicosatetraenoic acid (11,12-LTA4) was chemically synthesized from 12-hydroperoxy-eicosatetraenoic acid (12-HPETE). 11,12-LTA4 methyl ester was nonenzymically hydrolyzed to at least four products. These products were identified to be epimers of 5,12(S)-dihydroxy-eicosatetraenoic acid methyl ester (5,12(S)-diHETE-Me) and epimers of 11,12-diHETE-Me. In addition to the above nonenzymic products, 11,12-LTA4 was converted to 11,12-LTC4 by the rat liver glutathione S-transferase, and to an isomer of 11,12-diHETE by homogenates of the guinea pig adrenal gland and liver.

Adrenal Glands↗

PubMed1988

Synthesis and structural identification of four dihydroxy acids and 11,12-leukotriene C4 derived from 11,12-leukotriene A4.

Using a partially purified 12-lipoxygenase from porcine leukocytes, (5Z,8Z,10E,14Z)-12-hydroperoxy-5,8,10,14-icosate traenoic acid was synthesized from arachidonic acid with a yield of over 35%. The absolute configuration of C-12 was determined as S by chiral-phase column chromatography. It was chemically converted to at least three epoxides with the conjugated triene structure. Two were identified by proton NMR and mass spectrometry to be (5Z,7E,9E,14Z)-(11S,12S)-11,12-oxido-5,7,9,14-ic osatetraenoic acid (11,12-leukotriene A4) and (5Z,7Z,9E,14Z)-(11S,12S)-11,12-oxido-5,7,9,14-ic osatetraenoic acid (7-cis-11,12-leukotriene A4). 11,12-Leukotriene A4 underwent acid hydrolysis to yield two diastereomers of (6E,8E,10E,14Z)-(12S)-5,12-dihydroxy-6,8,10,14-i cosatetraenoic acid and two isomers of (14Z)-(12S)-11,12-dihydroxy-5,7,9,14-icosatetraenoic acid. Upon incubation with rat liver glutathione S-transferase, 11,12-leukotriene A4 was converted to 11,12-leukotriene C4, a spasmogenic compound.

Animals↗

PubMed1983

Studies on isoprenoid biosynthesis with bacterial intact cells.

For the study on the regulation of isoprenoid biosynthesis with intact cells, some strains of bacteria capable of growing on mevalonate as a sole carbon source were isolated from soil. Many of them incorporated [14C]-mevalonate, [14C]isopentenyl- and [14C]farnesyl pyrophosphates into the cells. However, radioactivity was found in their degradation products but not in isoprenoids. Addition of [14C]isopentenyl pyrophosphate, farnesyl pyrophosphate and Mg2+ ions in combination to the culture of a strain of Arthrobacter gave rise to 14C-incorporation into isoprenoids. Radioactivity was found in polyprenol, its pyrophosphate, monophosphate and fatty acid esters. The reactions of isopentenyl- and farnesyl pyrophosphates syntheses seemed to be rate-limiting steps.

Bacteria↗

PubMed1979