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Biomedical subjects

F Egami

Publications and source records attributed to F Egami.

At least 55 records · Page 3Linked to original sources
PubMed1975

Asparagusate dehydrogenases and lipoyl dehydrogenase from asparagus mitochondria.

1. Lipoyl dehydrogenase (NADH: lipoamide oxidoreductase, ED 1.6.4.3) and two asparagusate dehydrogenases from asparagus mitochondria were purified by a series of steps, freezing and thawing, sodium dodecylsulfate extraction, and chromatography on Sephadex G-200 and DEAE-cellulose. 2. Lipoyl dehydrogenase was highly specific for alpha-lipoic acid, which could not be replaced at all by asparagusic acid. Each of the asparagusate dehydrogenases was capable of reducing both asparagusic and alpha-lipoic acids by using NADH as hydrogen donor. 3. Reduction of alpha-lipoic cid with NADH by lipoyl dehydrogenase was activated by NAD, but that of asparagusic acid by asparagusate dehydrogenase was inactivated by NAD. 4. Lipoyl dehydrogenase and two asparagusate dehydrogenases differed in electrophoretic mobility on polyacrylamide gels.

Carboxylic Acids↗
PubMed1975

Copurification of L-ascorbate-2-sulfate sulfohydrolase and arylsulfatase activities from the liver of a marine gastropod, Charonia lampas.

Ascorbate-2-sulfate sulfohydrolase was purified 184-fold from a crude extract of the liver of Charonia lampas. In all purification steps including phosphocellulose, first and second Sephadex G-150 column chromatographies, the enzyme activity eluted together with arylsulfatase [ED 3.1.6.1] activity, and was separated from glycosulfatase ]EC 3.1.6.3] activity. The nonidentity of ascorbate-2-sulfate sulfohydrolase and glycosulfatase was further confirmed by an isoelectric focussing study. Ascorbate-2-sulfate sulfohydrolase had an isoelectric point, pI, of 4.9, and had maximum activity at pH 4.0. Its molecular weight was estimated to be about 154.000.

Animals↗
PubMed1975

Effects of various compounds on the ascorbate-2-sulfate sulfohydrolase and arylsulfatase activities copurified from the liver of Charonia lampas.

The effects of various compounds on ascorbate-2-sulfate sulfohydrolase and arylsulfatase (EC 3.1.6.1) activities in the copurified preparation from the liver of Charonia lampas were investigated. The former activity was competively inhibited by inorganic phosphate and sulfate. The latter was not affected by sulfate. Higher concentrations of sodium chloride inhibited the former and activated the latter. Neither of the activities was inhibited by sulfhydryl reagents. Both activities were competively inhibited by the other substrate.

Arylsulfatases↗
PubMed1975

Inhibition of Charonia lampas ascorbate-2-sulfate sulfohydrolase activity by adenosine 5'-diphosphate and related compounds.

1) ADP was a potent inhibitor of the ascorbic-2-sulfate sulfohydrolase activity of Charonia lampas liver. The inhibition was competitive with respect to ascorbate 2-sulfate. The Ki value was 5.9 muM. ADP did not inhibit arylsulfatase (EC 3.1.6.1) of the same organism. 2) Other nucleoside 5'-diphosphates and GTP showed similar inhibition of ascorbate-2-sulfate sulfohydrolase activity. 3) The effects of different nucleosides, nucleotides, and sugar phosphates on ascorbate-2-sulfate sulfohydrolase activity were investigated. Phosphate derivatives other than 3',5'-cyclic AMP were more or less inhibitory.

Adenosine Diphosphate↗
PubMed1975

Ascorbate 2-sulfate inhibits dopamine beta-hydroxylase reaction, but not ascorbate oxidase reaction.

Bovine adrenal dopamine beta-hydroxylase [EC 1.14.17.1] was considerably inhibited by ascorbate 2-sulfate. The inhibition was competitive with regard to ascorbate. The Ki value was 3.44 mM. The possibility that ascorbate 2-sulfate may play a regulatory role in the biosynthesis of norepinephrine is suggested. Another copper-containing oxidase, squash ascorbate oxidase [EC 1.10.3.3], was not inhibited by the same compound at a concentration of 150 mM.

Adrenal Medulla↗
PubMed1975

Effects of asparagusate and lipoate on enzymes of the tricarboxylic acid cycle and related metabolic pathways.

1. The effects of lipoate and asparagusate on animal and plant enzymes of the TCA cycle and related metabolic pathways were studied. 2. Lipoate inhibited bovine liver glutamate dehydrogenase [EC 1.4.1.3]. The inhibition may play a role in metabolic regulation. 3. Asparagusate inhibited lipoyl dehydrogenase [EC 1.6.4.3] from asparagus and lettuce competitively with respect to lipoate. Asparagusate had practically no effects on other asparagus enzymes. 4. Asparagusate strongly inhibited lipoyl dehydrogenase, glutamate dehydrogenase, and isocitrate dehydrogenase [EC 1.1.1.42] from animal sources, in competition with the corresponding substrate. 5. Asparagusate and lipoate also inhibited yeast glutamate dehydrogenase. 6. Based upon kinetic studies, the mode of these inhibitions is discussed.

Aconitate Hydratase↗
PubMed1975

Origin and early evolution of transition element enzymes.

In this paper we speculate on the origin and early evolution of transition element enzymes. Iron, molybdenum, and zinc, the most abundant transition elements in seawater, presumably complexed with compounds accumulated in the primeval sea in the course of chemical evolution forming compounds with subsequently evolved to form proenzymes or early enzymes with low activity and broad specificity. Iron complexes may be regarded as precursors of electron transfer enzymes, molybdenum complexes as precursors of enzymes involved in the metabolism of small molecules, and zinc complexes as precursors of hydrolytic and transferring enzymes, including enzymes participating in the metabolism of macromolecules and information transfer. The different iron, molybdenum, and zinc enzymes found in bacteria including Clostridium may then have arisen through specialization by increases in the enzyme specificity of these proenzymes. Copper would have been incorporated as an enzyme constituent after the elevation of environmental redox potential, probably due to the accumulation of atmospheric oxygen.

Aerobiosis↗