Power of the Secondary Sphere: Modulating Hydrogenase Activity in Nickel-Substituted Rubredoxin

ACS Catalysis ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 8928-8942 ◽  
Author(s):  
Jeffrey W. Slater ◽  
Sean C. Marguet ◽  
Michelle E. Gray ◽  
Haleigh A. Monaco ◽  
Marcos Sotomayor ◽  
...  
Keyword(s):  
Hydrogenase Activity

CORTICOSTEROID-UMSATZ UND CORTICOSTEROID-PRODUKTION BEI RATTEN UNTER DER BEHANDLUNG MIT ANABOLEN STEROIDEN

1965 ◽  
Vol 48 (2) ◽  
pp. 263-271 ◽  
Author(s):  
Herbert Schriefers ◽  
Gerlinde Scharlau ◽  
Franzis Pohl
Keyword(s):  
Production Rate ◽  
Adult Female ◽  
Anabolic Steroids ◽  
Reduction Rate ◽  
Female Rats ◽  
Adrenal Weight ◽  
Hydrogenase Activity ◽  
Anabolic Effect ◽  
Liver Slices

ABSTRACT After the administration of anabolic steroids to adult female rats in daily doses of 1 mg per animal for 14 days, the following parameters were investigated: the rate of the Δ4-5α-hydrogenase-catalyzed cortisone reduction in liver slices and microsomal fractions, the adrenal weight and the in vitro corticosterone production rate. Among the steroids tested, only 17α-methyl-testosterone and 17α-ethyl-19-nor-testosterone were effective in lowering significantly cortisone reduction rate by liver slices with concomitant decreases in microsomal Δ4-5α-hydrogenase-activity. Testosterone, 19-nor-testosterone, 17α-ethinyl-19-nor-testosterone, 17α-methyl-17β-hydroxy-androsta-1,4-dien-3-one and 1-methyl-17β-hydroxy-androst-1-en-3-one were ineffective or only slightly effective. Adrenal weight and absolute corticosterone production rate (μg/60 min per animal) were decreased after treatment with 17α-methyl-testosterone, 17α-ethyl-19-nor-testosterone and 1-methyl-17β-hydroxy-androst-1-en-3-one. Corticosterone production was decreased with 17α-ethinyl-19-nor-testosterone in spite of an unchanged adrenal weight. The relative corticosterone production rate (μg/60 min · 100 mg adrenal) was in any cases unaffected. According to these results there exists – with the exception of 17α-ethinyl-19-nor-testosterone – a strict parallelism between corticosteroid turnover and corticosterone production rate: unchanged turnover is correlated with unchanged corticosterone production rate, while a decreased turnover is correlated with decreased adrenal activity. The protein-anabolic effect of certain anabolic steroids may be partly due to an anti-catabolic action of these compounds resulting from a decreased corticosteroid inactivation and production rate. Possible mechanisms by which anabolic steroids may affect corticosteroid-balance are discussed.

Aerobic hydrogenase activity in Anacystis Nidulans The oxyhydrogen reaction

1979 ◽  
Vol 548 (2) ◽  
pp. 203-215 ◽  
Author(s):  
Günter A. Peschek
Keyword(s):  
Anacystis Nidulans ◽  
Hydrogenase Activity

Reaktionen der Hydrogenase aus Rhodopseudomonas capsulata im partikelgebundenen und gelösten Zustand

1969 ◽  
Vol 24 (5) ◽  
pp. 603-612 ◽  
Author(s):  
J.-H. Klemme
Keyword(s):  
Cytochrome C ◽  
Ammonium Sulfate ◽  
Deae Cellulose ◽  
Reaction Rates ◽  
Rhodopseudomonas Capsulata ◽  
Hydrogenase Activity ◽  
Original Activity ◽  
Dispersing Agent ◽  
Solubilized Enzyme ◽  
Triton X

In cell free extracts of Rps. capsulata obtained by exposure of cells to ultrasonic oscillation, about 90% of the hydrogenase is associated with the particulate chromatophore fraction. The particulate enzyme reacts with methylene blue (MB), menadione, phenazonium methosulfate (PMS), dichlorophenolindophenol (DCPIP), cytochrome c, p-benzoquinone (BQ), ferricyanide and O2,, but does not react with benzylviologen (BV), pyridinnucleotides and flavinnucleotides. Treatment of chromatophores with sodiumlaurylsulfate inactivates the hydrogenase reaction with PMS, DCPIP, BQ and ferricyanide. The MB-linked or menadione-linked hydrogenase is not destroyed by the detergent. The hydrogenase reaction with BV is increased more than 20-fold after incubation of the chromatophores with the lipid-dispersing agent. Treatment of chromatophores with acetone and petroleum ether almost completely inactivates the hydrogenase reaction with PMS and BQ. The reaction rate of the DCPIP-linked and the ferricyanide-linked hydrogenase is somewhat decreased, whereas the MB-linked, the menadione-linked and the BV-linked hydrogenase reactions still exhibit about 100% of the original activity. By extraction of the acetone-treated chromatophores with glycine-NaOH-buffer (pH 9), about 10 — 15% of the particulate hydrogenase is solubilized. The enzyme was 9-fold purified by ammonium sulfate precipitation and chromatography on DEAE-cellulose. The purified enzyme contains no cytochrome. The relative reaction rates of the solubilized enzyme with different electron acceptors are similar to the corresponding reaction rates of the acetonetreated chromatophores. Extraction of chromatophores with n-butanol results in the solubilization of 5 — 10% of the particulate enzyme. By extraction of acetone-treated chromatophores with 0,5% Triton X-100, 40% of the particulate hydrogenase is solubilized. The fractionation of the extract with ammonium sulfate results in the isolation of a cytochrome c-containing particle which exhibits a 3-fold increased hydrogenase activity.

Unconsidered factors affecting hydrogenase activity measurement

1984 ◽  
Vol 142 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Csaba Bagyinka ◽  
N.A. Zorin ◽  
Kornel L. Kovács
Keyword(s):  
Activity Measurement ◽  
Hydrogenase Activity ◽  
Factors Affecting

Immobilization of Desulfovibrio vulgaris cells with hydrogenase activity

2007 ◽  
Vol 50 (4) ◽  
pp. 563-570 ◽  
Author(s):  
M. C. Barreto ◽  
J. M. S. Cabral
Keyword(s):  
Desulfovibrio Vulgaris ◽  
Hydrogenase Activity

HYDROGENASE ACTIVITY AND PHOTOASSIMILATION

1982 ◽  
pp. 774-780
Author(s):  
MARTIN D. KAMEN
Keyword(s):  
Hydrogenase Activity

Hydrogen Evolution Catalyzed by Hydrogenase in Cultures of Cyanobacteria

1981 ◽  
Vol 36 (1-2) ◽  
pp. 87-92 ◽  
Author(s):  
Patrick C. Hallenbeck ◽  
Leon V. Kochian ◽  
John R. Benemann
Keyword(s):  
Hydrogen Production ◽  
Hydrogen Evolution ◽  
High Frequency ◽  
Nitrogenase Activity ◽  
Inhibitory Effect ◽  
Hydrogenase Activity ◽  
Oxygen Inhibition ◽  
Oxygen Sensitive

Abstract Cultures of Anabaena cylindrica, grown on media containing 5 mᴍ NH4Cl (which represses heterocyst formation), evolved hydrogen after a period of dark incubation under an argon atmosphere. This hydrogen production was not due to nitrogenase activity, which was nearly undetectable, but was due to a hydrogenase. Cultures grown on media with tungsten substituted for molybdenum had a high frequency of heterocysts (15%) and inactive nitrogenase after nitrogen starvation. The hydrogenase activity of these cultures was three-fold greater than the activity of non-heterocystous cultures. The effects of oxygen inhibition on hydrogen evolution by hetero-cystous cultures suggest that two pools of hydrogenase activity exist - an oxygen sensitive hydrogen evolution in vegetative cells and a relatively oxygen-resistent hydrogen evolution in heterocysts. In either case, inhibition by oxygen was reversible. Light had an inhibitory effect on net hydrogen evolution. Hydrogen production in vitro was much higher than in vivo, indicating that in vivo hydrogenase activity is limited by endogenous reductant supply.

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