SEARCH · PubMed Health

Results for “Chloromercuribenzoates”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 37 records · Page 2Linked to original sources

PubMed1995

[The effect of p-chloromercuribenzoate on regulation of oxidative phosphorylation by ADP and ATP and stimulation of liver mitochondrial respiration by palmitate].

The effect of p-chloromercuribenzoate (pCMB) on oxidative phosphorylation and palmitate-stimulated respiration of liver mitochondria has been studied. pCMB (1 microM) does not affect oxidative phosphorylation but reduces the inhibiting effect of ATP on this process. Used at the same concentration, pCMB eliminates the inhibiting effect of ADP and ATP on mitochondrial respiration in the presence of 10 and 20 microM palmitate. pCMB has no effect on inhibition of oxidative phosphorylation by carboxyatractyloside or on palmitate-stimulated respiration of mitochondria. It is concluded that the SH-groups of mitochondria localized in the hydrophilic region outside the inner mitochondrial membrane participate in regulation of oxidative phosphorylation by ATP and in regulation of palmitate-stimulated respiration by ADP + ATP.

Adenosine Diphosphate↗

PubMed2001

Study of the mechanism of action of p-chloromercuribenzoate on endonuclease from the bacterium Serratia marcescens.

The mechanism of action of p-chloromercuribenzoate (PCMB) on Serratia marcescens nuclease was investigated. The analysis showed that PCMB forms complexes with DNA. Binding of C7H5O2Hg+ to DNA changes the secondary structure of the DNA. These changes alter the enzymatic activity of S. marcescens nuclease, which was previously found to be sensitive to the secondary structure of the substrates. The nuclease activity was either suppressed or stimulated in the presence of PCMB depending on the C7H5O2Hg+ to nucleotide equivalent ratio. Binding of C7H5O2Hg+ to DNA did not form an abortive enzyme-substrate complex. Binding of Mg2+ to the C7H5O2Hg-DNA complex caused appropriate changes in secondary structure of the substrate. Since Mg2+ and C7H5O2Hg+, though differing in the type of metal cation, are similar in their mechanisms of influence on enzymatic activity of S. marcescens nuclease, the identity of other metal-containing effectors in their mechanism of action on Serratia marcescens nuclease is assumed.

Cations↗

PubMed2002

p-Chloromercuribenzoate-induced inactivation and partial unfolding of porcine heart lactate dehydrogenase.

Purified porcine heart lactate dehydrogenase was inactivated and partially unfolded with p-chloromercuribenzoate (pCMB). With the increase of pCMB/enzyme ratio the enzyme was gradually inhibited till almost completely inactivated at the pCMB/enzyme ratio of 20 : 1. Native polyacrylamide gel electrophoresis showed that with the increase of pCMB/enzyme ratio the bands of native enzyme decreased till completely vanished. Meanwhile inactive multiple bands emerged and became thicker, which implied that lactate dehydrogenase became loose. The conformational changes of the enzyme molecule modified with pCMB were followed using fluorescence emission, ultraviolet difference, and circular dichroism (CD) spectra. Increasing pCMB concentration resulted in the decrease of fluorescence emission intensity. The ultraviolet difference spectra of the enzyme modified with pCMB exhibited an increasing absorbance in the vicinity of 240 nm with the increasing concentration of the inhibitor. The changes of the fluorescence and ultraviolet difference spectra reflected the conformational changes of the enzyme. The CD spectrum changes of the enzyme showed that its secondary structure changed as well. These results suggest that pCMB not only inhibits this enzyme but also influences its conformation (partial unfolding).

Animals↗

PubMed1998

Activation mechanism and modification kinetics of Chinese hamster dihydrofolate reductase by p-chloromercuribenzoate.

Substrate effects on the activation kinetics of Chinese hamster dihydrofolate reductase by p-chloromercuribenzoate (pCMB) have been studied. On the basis of the kinetic equation of substrate reaction in the presence of pCMB, all modification kinetic constants for the free enzyme and enzyme-substrate binary and ternary complexes have been determined. The results of the present study indicate that the modification of Chinese hamster dihydrofolate reductase by pCMB shows single-phase kinetics, and that changes in the enzyme activity and tertiary structure proceed simultaneously during the modification process. Both substrates, NADPH and 7,8-dihydrofolate, protect dihydrofolate reductase against modification by pCMB. In the presence of a saturating concentration of NADPH, the value of kcat for 7,8-dihydrofolate in the enzyme-catalysed reaction increased four-fold on modification of Cys-6, accompanied by a two-fold increase in Km for the modified enzyme. The utilization of the binding energy of a group to increase kcat rather than reduce Km implies that the full binding energy of the group is not realized in the formation of the enzyme-substrate complex, but is used to stabilize the enzyme-transition-state complex.

Animals↗

PubMed1961

The inactivation of enterovirus infectivity by the sulfhydryl reagent p-chloromercuribenzoate.

The infectivity of several enteroviruses was inactivated by the sulfhydryl reagent p-chloromercuribenzoate (PCMB). The rate of inactivation was dependent on the ionic environment in which the reaction was carried out. Inactivation of infectivity was reversed by the thiol compound, reduced glutathione. Under certain conditions, PCMB prevented the adsorption of some enteroviruses to monolayer cultures of monkey kidney cells. The results suggest that enterovirus sulfhydryl groups are involved in the establishment of infection, and that they play a role in the adsorption of virus to host cells.

Benzoates↗

PubMed1975

Virucidal effect of sodium p-chloromercuribenzoate on influenza viruses attributable to inhibition of virus particle-associated RNA-dependent RNA polymerase.

Sodium p-chloromercuribenzoate (PCMB) caused a noticeable reduction of infectivity of prototype strains of type A and Lee strain of type B influenza viruses at concentrations of 100 and 200 mug/ml, respectively, after an incubation at 37 C for 60 min. The virucidal effect on A/AA/2/60 (H2N2) strain was dependent on the concentration of the drug and temperature as well as on the time of incubation. The reagent exerted this effect at a concentration which induced little change in the hemagglutinating and neuraminidase activities of the virus. PCMB inhibited by 50% the virus particle-associated RNA polymerase activity of all prototype strains of type A influenza virus at about 2 mug/ml and that of Lee strain of type B influenza virus at 8.5 mug/ml. Other sulfhydryl reagent such as phenylmercuric nitrate also exhibited virucidal effect on A/AA/2/60 virus which paralleled their inhibition of the virus particle-associated RNA polymerase activity. From these results it was considered likely that the virucidal action of PCMB on influenza viruses was attributable to inhibition of the virus particle-associated RNA polymerase activity.

Chloromercuribenzoates↗

PubMed1972

Evidence for specific inhibition of translocation of aminoacyl-transfer ribonucleic acid by the pretreatment of ribosomes of Bacillus subtilis with p-chloromercuribenzoate.

The biological activities of Bacillus subtilis ribosomes pretreated with 0.5, 1, or 2 mmp-chloromercuribenzoate (PCMB) were examined. The ribosomes treated with 1 or 2 mm PCMB lost their capacity to synthesize polyphenylalanine as well as the capacity to bind phenylalanyl-transfer ribonucleic acid. On the other hand, approximately 70% of the polyphenylalanine synthesis capacity was lost with ribosomes pretreated with 0.5 mm PCMB. This inhibition was found to be due to a specific inhibition of the translocation step. The effect of 0.5 mm PCMB was reversed by 20 mm Mg(2+) without the loss of PCMB bound to ribosomes, while beta-mercaptoethanol partially reversed the inhibitory effect with concomitant loss of bound PCMB.

Bacillus subtilis↗

PubMed1983

Effects of sulfhydryl reagent, p-chloromercuribenzoate, on p-aminohippurate transport by isolated, perfused snake renal tubules.

Effects of mercaptide-forming sulfhydryl reagent, p-chloromercuribenzoate (PCMB), on transport of p-aminohippurate (PAH) by isolated, perfused snake (Thamnophis species) renal tubules were studied. PCMB (10(-7) mol/l) in bathing medium irreversibly inhibited net transepithelial transport of PAH (JPAH) without affecting net fluid absorption (Jv). PCMB (10(-8) mol/l) in perfusate irreversibly inhibited JPAH without affecting Jv and markedly reduced the apparent permeability of the luminal membrane to PAH. These data suggest that sulfhydryl groups may be involved in the PAH transport steps at both the peritubular and luminal membranes.

Aminohippuric Acids↗

PubMed1979

Effect of leucine on the pyridine nucleotide contents of islets and on the insulin released--interactions in vitro with methylene blue, thiol oxidants, and p-chloromercuribenzoate.

In the presence of glucose (2 mg/ml), leucine (10 mM) noticeably increased islets' NADPH contents as well as the NADPH:NADP ratio; the changes occurred as soon as 1 min after its addition. NADH concentrations were also increased by leucine. The NADPH:NADP ratio as well as insulin release stimulated by glucose plus leucine were markedly decreased by methylene blue. The thiol oxidants diamide and tert-butyl hydroperoxide also inhibited insulin secretion in response to glucose plus leucine. Employing the perfused pancreas technique, the insulin-releasing action of p-chloromercuribenzoate was further enhanced by leucine. The combined effects were inhibited by tert-butyl hydroperoxide, however. Our data suggest that the insulin-releasing action of leucine depends on the islets' NADPH and reduced glutathione (GSH); in addition, leucine may contribute to insulin secretion by increasing the islet NADPH:NADP ratio and the NADH:NAD ratio. From the data, we assume that the observed increase of NADPH may lead via GSH to an increase in the number of such thiol groups in the beta-cell membrane, which are believed to be related to stimulation of insulin release and, thus, to increase the sensitivity of the beta-cell to stimulation by glucose and/or leucine.

Animals↗

PubMed1999

[The role of sulfhydryl groups in functioning of components of adenylate cyclase signal system in smooth muscles of the mollusk Anodonta cygnea (effect of N-ethylmaleimide and p-chloromercuribenzoic acid)].

The alkylating agent N-ethylameimide and the sulfhydryl group blocker p-chloromercuribenzoic acid (CPMA) inhibited in dose-dependent manner both basal activity of adenylyl cyclase (AC) and its activity stimulated by non-hormonal substances (forskolin, sodium fluoride, guanylilimidodiphosphate) in smooth muscles of the freshwater bivalve mollusk Anodonta cygnea. The double increase (from 30 to 60 min) in the time of preincubation of a sarcolemmal membrane fraction with ethylmaleimide and CPMA led to an essential increase in enzyme inhibition (especially for CPMA). 50 mM SH-containing reagent beta-mercaptoethanol (ME) partially restored the AC activity, inhibited by N-ethylmaleimide and CPMA, except when these two latter reagents were in high concentrations (1-10 and 0.5 mM, respectively). The data obtained point to the key role of cysteine SH-groups in regulation of the functional activity of proteins, components of the adenylyl cyclase system--AC and heterotrimeric G-proteins.

Adenylyl Cyclase Inhibitors↗

PubMed1987

Induction of Medicarpin Biosynthesis in Ladino Clover Callus by p-Chloromercuribenzoic Acid Is Reversed by Dithiothreitol.

Treatment of Ladino clover (Trifolium repens L.) callus with 1 millimolar p-chloromercuribenzoic acid (PCMBA) stimulated the biosynthesis of the phytoalexin medicarpin. Increased medicarpin concentration was detected at 6 hours, and maximum level was achieved by 36 hours. Dithiothreitol (DTT), added to callus at 2, 6, 10, and 18 hours following addition of PCMBA, partially counteracted the effect of PCMBA in the cells. The greatest effect on reversal of medicarpin accumulation was found at the earlier times for DTT addition. Compared to a 24-hour PCMBA control, final medicarpin concentrations were 9 to 19%, 37 to 45%, and 92 to 105% of the control value when DTT was added at 0.5, 1 or 2 hours, 3 or 4 hours, and 6, 8, 10, or 12 hours, respectively, after PCMBA addition. The results indicate that stimulation of medicarpin biosynthesis is reversible, but once activated, the pathway is not shut down by removal of elicitor.

Journal Article↗

PubMed1982