The 4-tert-Butylphenol-Utilizing BacteriumSphingobium fuliginisOMI Can Degrade Bisphenols via Phenolic Ring Hydroxylation andMeta-Cleavage Pathway

Thyroxine (T4) is the main product of thyroid secretion, a pro-hormone that must be activated by deiodination to T3 in order to initiate thyroid hormone action. This deiodination reaction occurs in the phenolic-ring (outer-ring deiodination, ORD) of the T4 molecule and is catalyzed by two selenocysteine-containing deiodinases, i.e. D1 and D2. As a counter point to the activation pathway, both T4 and T3 can be irreversibly inactivated by deiodination of the thyrosyl-ring (inner-ring deiodination, IRD), a reaction catalyzed by D3, the third member of the selenodeiodinase group. Due to its substantial physiological plasticity, D2 is considered the critical T3-producing deiodinase in humans. Recently, the observations made in the D1-deficient C3H mouse mice were expanded by the development of mice with generalized targeted disruption or cardiac-specific over-expression of the D2 gene. The results obtained indicate that the selenodeiodinases constitute a physiological system contributing with the thyroid hormone homeostasis during adaptation to changes in iodine supply, cold exposure, in patients with thyroid dysfunction and perhaps during starvation and illness.

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Chiral (salen) cobalt complexes encapsulated in mesoporous mordenite as an enantioselective catalyst for phenolic ring opening of terminal epoxides

Recent Progress in Mesostructured Materials - Proceedings of the 5th International Mesostructured Materials Symposium (IMMS2006), Shanghai, P.R. China, August 5-7, 2006 - Studies in Surface Science and Catalysis ◽

10.1016/s0167-2991(07)80361-2 ◽

2007 ◽

pp. 467-470 ◽

Cited By ~ 1

Author(s):

Kwang-Yeon Lee ◽

Young-Hee Lee ◽

Chang-Kyo Shin ◽

Geon-Joong Kim

Keyword(s):

Ring Opening ◽

Cobalt Complexes ◽

Phenolic Ring ◽

Enantioselective Catalyst

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Metabolism of 2-(α-naphthoxy)-N,N-diethyl propionamide in Tomato

Weed Science ◽

10.1017/s004317450003157x ◽

1973 ◽

Vol 21 (1) ◽

pp. 11-15 ◽

Cited By ~ 7

Author(s):

J. J. Murphy ◽

Janice Didriksen ◽

R. A. Gray

Keyword(s):

Lycopersicon Esculentum ◽

Water Soluble ◽

Tomato Plants ◽

Mechanical Harvester ◽

Ring Hydroxylation

Metabolism of the herbicide 2-(α-naphthoxy)-N,N-diethyl propionamide (R-7465) by tomato plants (Lycopersicon esculentum Mill. ‘Mechanical Harvester’) was investigated. Ring-labeled R-7465-14C was taken up rapidly by the roots and distributed throughout the leaves within 8 hr. R-7465 was converted primarily into water soluble metabolites. The principal metabolite was identified as a hexose conjugate of 2-(α-naphthoxy-4-hydroxy)-N,N-diethyl propionamide. This metabolite represented 47% of the soluble radioactivity in the plant. A different hexose conjugate of 2-(α-naphthoxy-4-hydroxy)-N,N-diethyl propionamide together with a hexose conjugate of 2-(α-naphthoxy-4-hydroxy)-N-ethyl propionamide accounted for another 22% of the radioactivity. Nonmetabolized R-7465 was found to represent only 5% of the total soluble radioactivity. Other identified metabolites included 2-(α-napthoxy)-N-ethyl propionamide, 2-(α-naphthoxy-5-hydroxy)-N,N-diethyl propionamide, and 1,4-naphthoquinone. None of these metabolites individually represented more than 3% of the soluble radioactivity in the plants. Ring hydroxylation and N-dealkylation appeared to be the initial steps in detoxification of R-7465 followed by conjugation with sugars.

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A Hybrid Density Functional Study of O−O Bond Cleavage and Phenyl Ring Hydroxylation for a Biomimetic Non-Heme Iron Complex

Inorganic Chemistry ◽

10.1021/ic035395c ◽

2004 ◽

Vol 43 (10) ◽

pp. 3277-3291 ◽

Cited By ~ 29

Author(s):

Tomasz Borowski ◽

Arianna Bassan ◽

Per E. M. Siegbahn

Keyword(s):

Phenyl Ring ◽

Density Functional ◽

Bond Cleavage ◽

Iron Complex ◽

Heme Iron ◽

Functional Study ◽

Density Functional Study ◽

Non Heme Iron ◽

Hybrid Density Functional ◽

Ring Hydroxylation

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Chiral (Salen) Complexes Encapsulated in Mesoporous ZSM-5 as an Optical Active Catalyst for Asymmetric Phenolic Ring Opening of Terminal Epoxides

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.1809 ◽

2007 ◽

Vol 124-126 ◽

pp. 1809-1812

Author(s):

Kwang Yeon Lee ◽

Young Hee Lee ◽

Chang Kyo Shin ◽

Geon Joong Kim

Keyword(s):

Ring Opening ◽

Acidic Solution ◽

Active Catalyst ◽

Immobilized Catalysts ◽

Phenolic Ring ◽

Salen Complexes ◽

Ring Opening Of Epoxides ◽

Very High ◽

Chiral Salen Complexes

ZSM-5 was modified by alkaline and acidic solution to introduce mesoporosity in the crystals. Heterogenized Co(III) salen was prepared in the mesopores of ZSM-5 by ‘ship-in-a-bottle’ method. Phenolic ring opening of epoxides was performed successfully by using encapsulated chiral salen catalysts. Very high enantioselectivity and conversion were obtained in PKR reaction by immobilized catalysts.

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Deiodination of l-thyroxine and its activity on the oxidation in vitro of reduced nicotinamide–adenine dinucleotide by peroxidase plus hydrogen peroxide

Biochemical Journal ◽

10.1042/bj1250869 ◽

1971 ◽

Vol 125 (3) ◽

pp. 869-878 ◽

Cited By ~ 8

Author(s):

Trinidad Jolin ◽

Gabriella Morreale De Escobar

Keyword(s):

Nicotinamide Adenine Dinucleotide ◽

Alternative Explanation ◽

Diphenyl Ether ◽

Reaction Medium ◽

Nadh Oxidation ◽

Phenolic Ring ◽

Active Moiety ◽

Reduced Nicotinamide Adenine Dinucleotide ◽

Competing Reactions

When l-thyroxine activates the oxidation of NADH by peroxidase+H2O2, little removal of phenolic-ring iodine atoms becomes apparent until most of the NADH has been oxidized, after which it increases markedly. This extensive deiodination is accompanied by loss of the ability of thyroxine to catalyse the oxidation of NADH by peroxidase+H2O2. The slight deiodination observed before the appearance of extensive deiodination is somewhat higher when the effect of thyroxine on NADH oxidation is greater, and lower when thyroxine has exerted a slighter effect. ICN (but not I2 or thyronine) catalyses NADH oxidation, in both the presence and the absence of peroxidase+H2O2: thyroxine+peroxidase+H2O2 are thus comparable with ICN alone in their effects on NADH oxidation. The obvious conclusion from the above observation, namely that the active moiety is the halogen liberated from thyroxine (or ICN) is, however, not directly supported by some of the results obtained by measuring the degree of deiodination of thyroxine in the system. In an attempt to reconcile some apparently contradictory conclusions, it is suggested that, when thyroxine activates oxidation of NADH by peroxidase+H2O2, the diphenyl ether structure is undergoing cyclic deiodination and iodination. This would be accompanied by the maintenance in the reaction medium of an oxidized form of iodine, similar to that liberated by ICN, which would be the actual active moiety, until the NADH concentration becomes so low that the diphenyl ether structure is ruptured oxidatively. An alternative explanation is that thyroxine is oxidized to a form that either oxidizes NADH or loses iodine in competing reactions.

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