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At least 19 recordsLinked to original sources
PubMed1986

L-[3H]lysine binding to rat retinal membrane: II. Effect of kainic acid, D,L-alpha-aminoadipic acid, iodoacetic acid, and modification by dark-exposure.

The rat retina and the different brain regions contain membranes sites that bind L-lysine in the nanomolar range. These binding sites undergo changes in different experimental conditions, thus: intraocular injection of kainic acid induces a reduction of the density of L-lysine binding sites, D,L-alpha-aminoadipic acid injected into the eye enhances both kinetic parameters (Bmax and Kd) of L-[3H]lysine binding sites, the intraperitoneal injection of iodoacetic acid decreases the sensitivity for its ligand binding sites, and the exposure to darkness of the rats reduces L-[3H]lysine binding in the retina, thalamus, hypothalamus and superior colliculus, but not in the occipital cortex; such a decrease appears to be characterized, at least in the retina, by a lower sensitivity of the binding sites for L-lysine after the exposure to darkness. The results show that L-lysine binding sites are located on kainic acid-sensitive cells and can be involved in the physiological mechanism of vision.

2-Aminoadipic Acid↗
PubMed1981

Affinity labelling of liver alcohol dehydrogenase. Effects of pH and buffers on affinity labelling with iodoacetic acid and (R, S)-2-bromo-3-(5-imidazolyl)propionic acid.

Both iodoacetic acid and (R,S)-2-bromo-3-(5-imidazolyl)propionic acid (BrImPpOH) react with liver alcohol dehydrogenase in an affinity labelling mechanism between pH 6.1 and 10.5. The buffer-independent dissociation constants and the first-order rate constants have been determined as a function of pH. With BrImPpOH a pKa close to 9 for the free enzyme is assigned to the zinc-water ionization. The buffers used exerted a protective effect upon the inactivation of the enzyme by iodoacetic acid and BrImPpOH. Phosphate buffer showed a high degree of protection especially at lower pH, while zwitterionic buffers like Mes (4-morpholineethanesulfonic acid), Pipes (1,4-piperazinediethanesulfonic acid), Epps [4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid] and Bicine [N,N-bis(2-hydroxyethyl)glycine] gave less protection to various degrees. An exception was Ches (cyclohexylaminoethanesulfonic acid) which had an anomalously high affinity for the iodoacetate binding site. The dissociation constants of the buffers were calculated for the case of inactivation by both iodoacetic acid and BrImPpOH.

Affinity Labels↗
PubMed1990

The effect of iodoacetic acid on the electroretinogram and oscillatory potentials in rabbits.

It has been shown that a single injection of iodoacetic acid selectively (but temporarily) abolishes the b-wave of the electroretinogram. We examined whether such use of this chemical further substantiate our claim that the b-wave of the electroretinogram is a composite potential resulting from the summation (or integration) of faster retinal potentials, usually referred to as the oscillatory potentials. Full-field electroretinograms were recorded from adult New Zealand rabbits before and after a single, bolus injection of 15 mg/kg of buffered iodoacetic acid. Both the 1-1000 Hz electroretinogram and the 100-1000 Hz oscillatory potentials were recorded simultaneously. The oscillatory potentials considered in this study were those normally seen on the rising phase of the b-wave. Following the intravenous injection of iodoacetic acid, there was a progressive decrease in the amplitude and peak time of the b-wave. This observation also was reflected in the oscillatory potential recordings, in which the long-latency oscillatory potentials (3 and 4) progressively disappeared while oscillatory potential 2 remained. We believe that these findings further support our contention that the oscillatory potentials are major components of the b-wave.

Animals↗
PubMed1987

Iodoacetic acid and related sulfhydryl reagents fail to inhibit cell-cell communication: mechanisms of immunotoxicity in vitro.

The present study was undertaken to examine the effects of iodoacetic acid, a non-phorbol tumor promoter, on metabolic cooperation between mutant human fibroblasts as measured by [14C]citrulline incorporation. Other thiol-reactive polyphenolic compounds such as hydroquinone and 2-hydroxyestrone were also examined. 12-O-Tetradecanoyl phorbol-13-acetate (TPA), a potent skin tumor promoter, inhibited the cell-cell communication by more than 60% at 20 ng/ml. However, iodoacetic acid, hydroquinone, and 2-hydroxyestrone, had no effect on the process even at cytotoxic concentrations. Induction of intercellular contact (agglutination) among lymphocytes during the course of phytohemagglutinin (PHA)-induced blastogenesis was monitored turbidometrically at 620 nm. Hydroquinone and 2-hydroxyestrone suppressed the PHA-induced lymphocyte agglutination at 1-2 microM in vitro concentrations while iodoacetic acid was devoid of any effects at concentrations up to 100 microM. Hydroquinone and 2-hydroxyestrone concomitantly suppressed PHA-induced lymphocyte blastogenesis at 1-2 microM in vitro concentrations while the suppression by iodoacetic acid was significant at 10 microM. All 3 compounds failed to disrupt microtubule assembly, a sulfhydryl-dependent process, in a rat brain crude extract. However, p-benzoquinone, an oxidation product of hydroquinone, did inhibit the process at 1 mM. In summary, these studies suggest that, unlike TPA, thiol-reactive non-phorbol tumor promoters and polyphenolic compounds do not inhibit cell-cell communication between mutant human fibroblasts. Although the compounds demonstrate diverse molecular mechanisms of action, they all inhibit in vitro immune functions suggesting that immunosuppression may play a role in tumor promotion.

Agglutination↗
PubMed1982

The specificity of active-site alkylation by iodoacetic acid in the enzyme thiosulfate sulfurtransferase.

The active-site sulfhydryl group in the enzyme thiosulfate sulfurtransferase (rhodanese; thiosulfate:cyanide sulfurtransferase; EC 2.8.1.1) is alkylated rapidly by iodoacetic acid in the free enzyme form, E, with complete loss of sulfurtransferase activity. Iodoacetic acid is completely ineffective with the sulfur-substituted form of the enzyme, ES. Iodoacetamide, on the other hand, has no effect on either enzyme form. The competitive enzyme inhibitor, toluenesulfonic acid, protects against inactivation in a strictly competitive way and analysis gives an apparent binding constant for toluenesulfonic acid of 12.5 mM, which is in agreement with studies of its effect on the catalyzed reaction. These results are taken to indicate that iodoacetic acid is an affinity analog for the substrate, thiosulfate, and inactivates because it can use the specific thiosulfate binding interactions, correctly orient its reactive center and displace intraprotein interactions which appear to protect the active-site sulfhydryl group in the E form.

Alkylation↗
PubMed2003

[Iodoacetic acid as a potential elicitor of increased production of flavonoids in a culture of Ononis arvensis L. in vitro].

The paper tested the effect of iodoacetic acid in four different concentrations on the production of flavonoids in the callus and suspension culture of Ononis arvensis L. The elicitor was in contact with the culture for a period of 6; 24; 47; 72, and 168 hours. The obtained results show a statistically significant increase in the content of flavonoids in the suspension culture in comparison with the control in the use of all tested concentrations of the elicitor after 6; 24; 48, and 72 hours of elicitation. The maximal increase by 586% in the production of flavonoids in the suspension culture took place with the use of iodoacetic acid in a concentration of 1 mg/l. In the callus culture, the maximal increase in the formation of flavonoids occurred with the use iodoacetic acid in a concentration of 10 mg/l after 24 hours of elicitation, the content of flavonoids being increased by 529% in comparison with the control.

Culture Techniques↗
PubMed1988

Restoration of enzymic activity and cytotoxicity of mutant, E553C, Pseudomonas aeruginosa exotoxin A by reaction with iodoacetic acid.

Pseudomonas aeruginosa exotoxin A (ETA) is inactivated greater than 1,000-fold when an active site glutamic acid, E553, is mutated to aspartic acid (Douglas, C.M., and Collier, R. J. (1987) J. Bacteriol. 169, 4967-4971). To test the effect of creating a carboxyl-containing side chain at position 553 longer than that of glutamic acid, we first replaced Glu-553 with cysteine by site-directed mutagenesis of cloned ETA and then carboxymethylated the cysteine side chain with iodoacetic acid. The E553C mutation reduced ADP-ribosyltransferase and cytotoxic activities greater than 10,000-fold. Reaction of the mutant with iodoacetic acid enhanced enzymic activity 2,500-fold, to a level approximately one-sixth that of wild type toxin, and restored cytotoxicity to a slightly lesser extent. Iodoacetamide did not activate the mutant, and neither iodoacetic acid nor iodoacetamide affected the activity of wild type toxin. These results show that the carboxyl group of Glu-553 is important for ADP-ribosylation activity and imply flexibility in the enzyme-substrate complex in accommodating the slightly longer S-carboxymethylcysteine side chain. This general approach may have applications in protein engineering as well as in studying carboxyl side chain functions in enzymes.

ADP Ribose Transferases↗
PubMed2006

Formation of iodoacetic acids during cooking: interaction of iodized table salt with chlorinated drinking water.

Iodoacetic and chloroiodoacetic acids were formed when municipal chlorinated tap water was allowed to react with iodized (with potassium iodide) table salt or with potassium iodide itself. Iodoacetic acid was recently shown to be a potent cytotoxic and genotoxic agent. For analysis, samples were extracted with t-amyl methyl ether and converted to the corresponding methyl esters using methanol and sulfuric acid. The concentration of iodoacetic acid was determined by gas chromatography-mass spectrometry (GC-MS) using an authentic standard. The identities of iodoacetic and chloroiodoacetic acids were further confirmed by gas chromatography-high-resolution mass spectrometry (GC-HRMS). Certain influences of sodium hypochlorite and humic acid as well as the concentration of potassium iodide on the yields of these acids were investigated. The concentration of iodoacetic acid in tap water samples boiled with 2 g l-1 of iodized table salt was found to be in the 1.5 microg l-1 range, whilst the concentration of chloroiodoacetic acid was estimated to be three to five times lower.

Chlorine↗
PubMed1995

Conjugation to preactivated proteins using divinylsulfone and iodoacetic acid.

Two methods for the preactivation of proteins and conjugation of peptides to proteins under mild conditions are presented. Preactivation of proteins with divinylsulfone (DVS) permits peptide conjugation through either amino, hydroxyl or sulphydryl groups depending on the coupling pH used, while preactivation with iodoacetic acid (IAA) N-hydroxy-succinimide ester permits selective conjugation through sulphydryl groups. In addition, the latter method allows quantitation of the conjugation ratio through determination of carboxymethyl cysteine after acid hydrolysis. The divinylsulfone activated proteins can be stored for extended periods of time at -20 degrees C until required for conjugation, while the iodoacetic acid activated protein can be stored for a few days at -20 degrees C. These conjugation methods were investigated with respect to obtaining peptide/protein conjugates for immunization purposes and for use as reagents in immunoassays. The DVS activated proteins permitted direct conjugation of luteinizing releasing hormone (LHRH) through its tyrosine side chain and allowed synthesis of well defined conjugates. The DVS derivatives of bovine serum albumin (BSA), reduced and carboxymethylated BSA and purified protein derivative (PPD) were compared with respect to their potential value as carriers for obtaining antibodies to LHRH (M(r) 1000) and epidermal growth factor (EGF, M(r) 5000). IAA-PPD was evaluated as a carrier for the conjugation of glutathione specifically through its cysteine side chain and for obtaining antibodies to glutathione. The antisera obtained were specific and of high titer, and the methods described here will thus allow the convenient synthesis of carrier conjugates with well defined characteristics.

Amines↗
PubMed1997

Different efficacy of iodoacetic acid and N-ethylmaleimide in high-performance liquid chromatographic measurement of liver glutathione.

The widely used high-performance liquid chromatography (HPLC) procedure to determine glutathione in biological samples utilizing iodoacetic acid as thiol quenching agent and 1-fluoro-2,4-dinitrobenzene for derivatization has been modified regarding tissue sample processing and storage of the working solutions. The modified procedure compared with the original method reduces artifactual oxidation in rat liver glutathione measurement (1.47+/-0.8% vs. 2.84+/-0.69%, respectively). In both HPLC procedures, an increase in artifactual oxidation was found in both standard glutathione solutions and hepatic samples when N-ethylmaleimide instead of iodoacetic acid was used for thiol trapping.

Animals↗
PubMed1988

[Perifusion of monolayer-cultured B cells of the infant rat: a comparative study of the effects of 2-deoxy-2-fluoroglucose and iodoacetic acid].

Cell culture techniques for monolayer islets of 3-week-old rat pancreases and the responsiveness of B cells are described. In this procedure, whole pancreatic tissues from 3-week-old rats were enzymatically dispersed and then cultured in a medium with 5.5 mM glucose plus 1 mM 2-deoxy-2-fluoroglucose or with 5.5 mM glucose following a 3-day exposure to a medium with 5.5mM glucose plus 5 microM iodoacetic acid. The use of 2-deoxy-2-fluoroglucose or iodoacetic acid allowed a selective deletion of fibroblasts, yielding large clusters that consisted mostly of islet cells. The immunocytochemical evaluation of the islet cells in these cultures showed that approximately 70% are B-cells, 20% A-cells, and 10% D-cells. On day 0, the response to 16.7 mM glucose included only a small rise in insulin secreted during the first and the second phase, and the response to 10 mM of leucine or 2-ketoisocaproate was monophasic. After being cultured for 7 days, all three secretagogues markedly stimulated insulin secretion by B cells cultured in both media, resulting in an enhancement of the biphasic pattern. However, quantitative relationships differed. Thus, the total response from B cells in 2-deoxy-2-fluoroglucose during a 30-min stimulation with glucose and leucine was significantly higher (1.6- and 1.9-fold respectively) than that from B cells in 5.5 mM glucose, although there was no significant difference in insulin secretion evoked by 2-ketoisocaproate. Furthermore, in the former B cells, the amount of insulin secreted during the second phase was 84-94% of the total insulin secretion, and in the latter it was 66-76%. Addition of 1 mM 3-isobutyl-1-methylxanthine and 10 microM forskolin resulted in a significant increase in insulin secretion by B cells in 2-deoxy-2-fluoroglucose, whereas there was no difference in the increase of insulin secretion induced by 16.7 mM glucose and 200 nM 12-o-tetradecanoyl phorbol-13-acetate. In monolayer cultures that had been maintained in both media for 15 days, the second phase of insulin secretion due to the secretagogues was slightly decreased, but the biphasicity in the response was well preserved. In conclusion, the present results suggest that B cells of 3-week-old rats may be still immature, and that the medium with 2-deoxy-2-fluoroglucose is beneficial to the continued maturation of the B-cell function in vitro.

Animals↗
PubMed1981

Effects of iodoacetic acid on relaxation parameters of the rabbit papillary muscle.

Measurements have been made of isometric contractions and diastolic oscillations (after-contractions) in right ventricular rabbit papillary muscles at a temperature of 14.5 degrees C. The relaxation courses can be described as damped harmonic oscillations superposed on an exponential descending carrier function by using a model with six parameters. The influence of iodoacetic acid (10(-4) M) was investigated on contraction and relaxation parameters which result from approximation of the measured force values. The following changes were observed: 1. Decrease of the contraction height as well as of the amplitudes of diastolic oscillations. 2. Increase in the damping ratio and in the period of diastolic oscillations both calculated from relaxation parameters. 3. Diminution of the force range which is passed by the carrier function within 6 s of relaxation time accompanied by a transition to contracture. A fast and a slow Ca sequestration process are supposed to exist. The results indicate that both of them are influenced by iodoacetic acid.

Animals↗
PubMed1981

Cytoplasmic estrogen receptor system of gilt uterus. Partial purification of component B labeled with [14C]iodoacetic acid.

Analysis of the cytoplasmic estrogen receptor (ER) system of gilt uterus by protecting ER from proteolysis showed that the ER system of gilt uterus is similar to that of cow uterus described previously. There was only one native unit molecule [native "4S" ER (sedimentation coefficient, 4.5S; Stokes radius, 45 A; molecular weight, 82,000)] with specific affinity towards estradiol. This molecule was further designated as vero-ER. "8S" ER-forming factor [("8S"ER)-FF] (Stokes radius, 51 A) was separated from the cytosol under hypotonic (low salt) conditions, and this was further dissociated into component A ["5S" ER-forming factor, ("5S"ER)-FF] (Stokes radius, 37 A) and component B (Stokes radius, 18.5 A) in the presence of sodium thiocyanate. Vero-ER was proteolyzed in the absence of Ca2+ ion by a cytoplasmic protease into modified "4S" ER (sedimentation coefficient, 4.5S; Stokes radius, 35 A; molecular weight, 65,000) which was further designated as secto-ER. The constituents of the cytoplasmic ER system of cow and gilt uteri cross-reacted with each other to undergo similar molecular assembly as in their own systems. When analyzed for various uterine specimens, fluctuation of ("8S"ER)-FF-level (1-50 unit/g tissue) was more remarkable than that of ER-level (3-6 x (10(-12) mol/g tissue). Component B labeled with [14C]iodoacetic acid was purified over 1,500-fold. Mixture of vero-ER and component B labeled with [14C]iodoacetic acid formed "6S' ER with 14C-activities under hypotonic conditions. This clearly excluded the possibility that component B is a catalyzer of self-association (dimerization) of vero-ER.

Animals↗
PubMed1976

Production and rejoining of single-strand breaks in DNA of Escherichia coli cells after exposure to gamma-rays in the presence of iodoacetic acid under oxic and anoxic conditions.

The presence of iodoacetic acid (IAA, 10(4) M) during exposure of Escherichia coli cells to 25 krad gamma-radiation under anoxia resulted in a greater number of radiation-induced single-strand scissions in DNA. The single-strand breaks produced under oxic conditions of irradiation, however, were only marginally increased when IAA was present during irradiation. Although cells irradiated under anoxic or oxic condition and those irradiated under anoxic condition in the presence of IAA were capable of rejoining single-strand breaks produced in DNA, those irradiated under oxic condition in the presence of IAA had lost this capacity.

DNA Repair↗