Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Dimercaprol”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
PubMed1982

On the role of ubiquinone in the respiratory chain.

(1) The V1 (substrate-Q oxidoreductase activity) and V2 (QH2 oxidase activity) for the oxidation of substrates by submitochondrial particles have been measured by using heptylhydroxyquinoline N-oxide (HQNO) as inhibitor of V2. (2) Partial destruction of the Rieske Fe-S cluster by treatment with Bal (2,3-dimercaptopropanol) + O2 has the same effect on the QH2 oxidase activity as partial saturation of the antimycin-binding site with HQNO. (3) The extent of the rapid reduction of cytochrome b in the presence of excess antimycin is proportional to the percentage of intact Rieske Fe-S cluster. (4) The measured rate of oxidation of endogenous ubiquinol (V2) by submitochondrial particles is dependent on the substrate used to reduce ubiquinone, especially at low levels of ubiquinone. (5) Pool-function kinetics in the oxidation of substrate, found both in the presence and absence of free ubiquinone, are due both to the pool of free ubiquinone and to direct collision between Q-loaded Q-reducing and -oxidizing enzymes. At infinite Q content only the former mechanism is operative; at low Q content only the latter. (6) Duroquinone can be reduced directly by NADH dehydrogenase without mediation of ubiquinone, but duroquinol cannot be oxidized in the absence of ubiquinone. On the other hand, the reduction of cytochrome b by duroquinol does not require the presence of ubiquinone. (7) It is suggested that the need for ubiquinone for the oxidation of duroquinol is due to the requirement of ubisemiquinone for the oxidation of cytochrome b, duroquinol not being able to form a stabilized semiquinone.

Animals↗
PubMed1986

The effect of ring substituents on the mechanism of interaction of exogenous quinones with the mitochondrial respiratory chain.

In uncoupled pig-heart mitochondria the rate of the reduction of duroquinone by succinate in the presence of cyanide is inhibited by about 50% by antimycin. This inhibition approaches completion when myxothiazol is also added or British anti-Lewisite-treated (BAL-treated) mitochondria are used. If mitochondria are replaced by isolated succinate:cytochrome c oxidoreductase, the inhibition by antimycin alone is complete. The reduction of a plastoquinone homologue with an isoprenoid side chain (plastoquinone-2) is strongly inhibited by antimycin with either mitochondria or succinate:cytochrome c reductase. The reduction by succinate of plastoquinone analogues with an n-alkyl side chain in the presence of mitochondria is inhibited neither by antimycin nor by myxothiazol, but is sensitive to the combined use of these two inhibitors. On the other hand, the reduction of the ubiquinone homologues Q2, Q4, Q6 and Q10 and an analogue, 2,3-dimethoxyl-5-n-decyl-6-methyl-1,4-benzoquinone, is not sensitive to any inhibitor of QH2:cytochrome c reductase tested or their combined use, either in normal or BAL-treated mitochondria or in isolated succinate:cytochrome c reductase. It is concluded that quinones with a ubiquinone ring can be reduced directly by succinate:Q reductase, whereas those with a plastoquinone ring can not. Reduction of the latter compounds requires participation of either center i or center o (Mitchell, P. (1975) FEBS Lett. 56, 1-6) or both, of QH2:cytochrome c oxidoreductase. It is proposed that a saturated side chain promotes, while an isoprenoid side chain prevents reduction of these compounds at center o.

Animals↗
PubMed1989

Involvement of thiol groups in the function of the dipeptide/proton cotransport system in rabbit renal brush-border membrane vesicles.

The role of thiol groups in H+-gradient-dependent dipeptide transport in rabbit renal brush-border membrane vesicles was investigated using glycylsarcosine as the substrate. Treatment of the membrane vesicles with a thiol-group-reducing agent, dimercaptopropanol, stimulated Gly-Sar transport. On the other hand, treatment with thiol group oxidants such as 5,5'-dithiobis(2-nitrobenzoic acid), plumbagin and phenazine methosulfate inhibited Gly-Sar transport. These effects were irreversible, because washing the membranes after treatment failed to reverse the effects. Incubation of the membrane vesicles with phenylarsine oxide, a reagent which interacts specifically with vicinal dithiols, significantly inhibited Gly-Sar transport. In all cases, the stimulation or the inhibition of the dipeptide transport was primarily due to changes in the maximal velocity of the transport system, the apparent affinity constant remaining unaltered. These results demonstrate the involvement of one or more vicinal dithiol groups in the function of the renal dipeptide transport system and that these thiol groups must exist in reduced form to maintain maximal transport activity. In addition, these data indirectly suggest that a dithiol-disulfide interchange may play a role in the function of the renal dipeptide transport system.

Animals↗
PubMed1980

Action of oxidized and reduced glutathione on rabbit red blood cell hexokinase.

Reduced glutathione at 1 mM concentration is able to mantain rabbit red blood cell hexokinase (EC 2.7.1.1) in the reduced state with fully catalytic activity. At higher concentrations a marked inhibition is observed. In contrast, oxidized glutathione is a strong inhibitor of reduced erythrocyte hexokinase at all the concentration studied. Inactivation experiments show that some sulfhydryl groups reacting with oxidized glutathione are responsible for the enzyme inactivations. These findings suggest a cellular inter-relationship between redox and energetic metabolism coupled through glutathione at the hexokinase level.

Adenosine Triphosphate↗