Dithioerythritol Research Articles

Nuclear magnetic resonance and potentiometric studies of the complexation of methylmercury(II) by dithiols

Complexation of methylmercury, CH3Hg(II), by 2,3-dimercaptosuccinic acid (DMSA), 2,3-dimercaptopropanesulfonate (DMPS, Unithiol), dithioerythritol (DTE), and 2,3-dimercaptopropanol (British AntiLewisite, BAL) has been studied by 1H nuclear magnetic resonance spectroscopy and by potentiometric titration. In the nmr study, the equilibrium constants for displacement of mercaptoacetate from its CH3Hg(II) complex by the dithiols were determined over a wide pH range, from mercaptoacetate chemical shift data. Similar competition reactions between the dithiols and mercaptoethanol were used in the potentiometric study. Using previously determined CH3Hg(II) formation constants for the competing ligands, equilibrium constants for the formation of mono- and bis-CH3Hg(II) complexes with the dithiols have been determined. The formation constants for the mono-CH3Hg(II) complexes with the vicinal dithiols BAL and DMPS are significantly higher than expected by consideration of the basicity of the sulfhydryl donors, in comparison with those for DMSA, non-vicinal DTE, and monothiols. We interpret this to indicate chelation of CH3Hg(II) by BAL and DMPS but not by DMSA. The conditional formation constants at physiological pH are discussed with reference to the effectiveness of BAL, DMPS, and DMSA as antidotes for methylmercury poisoning. In particular, the constants obtained indicate that, for dithiol antidotes at concentrations greater than that of methylmercury (II), methylmercury(II) complexes formed at physiological pH are of 1:1 stoichiometry. For BAL, a substantial proportion of the complex will be in the neutral form, in contrast to DMPS and DMSA which form anionic species only.

A new radiochemical method for determination of pyruvate dehydrogenase complex and acetyl-coenzyme a synthetase

A radiochemical method for assaying pyruvate dehydrogenase complex and acetyl-coenzyme A synthetase is described, using [2- 14C]pyruvate and [1- 14C]acetate, respectively, as radiolabeled precursors. The assay is based on nonenzymatic O-acylation of excess dithioerythritol (DTE) by enzymatically formed acetyl-coenzyme A. [1- 14C]Acetyl-DTE is easily extracted from the incubation mixture by organic solvents and separated from the unreacted labeled substrates.

S-Ethyl dipropylthiocarbamate, N,N-Diallyl-2-chloroacetamide, and 2-chloroallyl diethyldithiocarbamate influence on sulfhydryl-dependent sucrose accumulation

l-[U- 14C]sucrose accumulation by phloem sieve tube members (PSTM) of wheat ( Triticum aestivum L. ‘Holley’) and sorghum ( Sorghum bicolor L. ‘G522 DR’) was inhibited by the nonpermeant sulfhydryl inhibitor p-chloromercuribenzenesulfonic acid (PCMBS), and this inhibition was reversed by the permeant sulfhydryl protectants dithiothreitol (DTT) and dithioerythritol (DTE). S-Ethyl dipropylthiocarbamate (EPTC) (≤0.1 m M) did not inhibit [ 14C]sucrose accumulation by wheat or sorghum PSTM. N-N-Diallyl-2-chloroacetamide (CDAA) (1 m M) inhibited [ 14C]sucrose accumulation by sorghum but not by wheat PSTM. The inhibition of [ 14C]sucrose accumulation in sorghum PSTM by the membrane permeant CDAA was reversed by DTT. Sorghum growth was inhibited by <1 μ M CDAA. Membrane permeant 2-chloroallyl diethyldithiocarbamate (CDEC) (0.1 m M) inhibited [ 14C]sucrose accumulation by PSTM of sorghum but not wheat. The inhibition of sucrose accumulation in sorghum PSTM by 0.1 m M CDEC was reversed by DDT.

Evidence for the involvement of essential sulphydryl group in rat hepatic lactogenic receptor but not in somatogenic receptor

Incorporation of P-chloromercuribenzene sulphonate (PCMBS) (1mM) in the assay medium for rat hepatic lactogenic receptor produced complete inhibition of binding of [ 125I]oPRL to the membrane. However, the presence of the thiol-reactive agent produced no effect on the binding of [ 125I]bGH to rat hepatic somatogenic receptor. Pretreatment of rat hepatic membrane with PCMBS inhibited the binding of [ 125I]oPRL but not that of [ 125I]bGH. The lactogenic receptor binding inhibition by PCMBS pretreatment was both concentration- and time-dependent, with complete inhibition at 0.5 mM for 60 min at 0°C. Scatchard analysis of [ 125I]oPRL binding to membrane at 50% inhibition by PCMBS (0.11 mM) revealed that the binding capacity was decreased rather than the binding affinity. Furthermore, the inhibition of lactogenic receptor binding by PCMBS could be reversed by dithioerythritol (DTE) treatment. Following 80% inhibition by 0.2 mM PCMBS, full recovery of receptor binding was achieved at 6 mM DTE for 60 min at 0°C. The ‘recovered’ membrane showed no difference from the control membrane in terms of binding capacity and affinity.

Isolation and characterization of thiosulfate reductases from the green alga Chlorella fusca

Thiosulfate-reductase activity (TSR) measured as sulfide release from thiosulfate was detected in crude extracts of Chlorella using dithioerythritol (DTE) as electron donor. Purification of this activity by ammonium-sulfate precipitation between 35% and 80% followed by Sephadex G-50 gel filtration, diethylaminoethyl-cellulose chromatography, and gel filtration on Biogel A 1.5 M led to four distinct proteins having molecular weights of: TSR I, 28000; TSR II, 26500; TSR IIIa, 55000; TSR IIIb, 24000 daltons. These thiosulfate reductases were most active with DTE; the monothiols glutathione, L-cysteine, and β-mercaptoethanol had little activity towards this system. The following pH optima were obtained: for TSR I and TSR II, 9.0; for TSR IIIa, 8.5; and for TSR IIIb, 9.5. The apparent-Km data for DTE and thiosulfate were determined to: [Formula: see text] TSR I, 0.164 mmol·l(-1) and TSR II, 0.156 mmol·l(-1); KmDTE TSR I, 1.54 mmol·l(-1) and TSR II 1.54 mmol·l(-1). The thiosulfate reductases IIIa and IIIb were further stimulated by addition of thioredoxin. All TSR fractions catalyzed SCN formation from thiosulfate and cyanate and thus had rhodanese activity; this activity, however, could only be detected in the presence of thiols.

Chlorpromazine and dithioerythritol protection against acute ethanol toxicity.

Our previous work has shown that an increase in body temperature increases the acute toxicity of ethanol in mice. To determine whether a decrease in body temperature would have the opposite effect, we studied the effect of two substances that decrease body temperature (chlorpromazine (CPZ) and dithioerythritol (DE)) on ethanol toxicity. Matched groups of 10 mice were injected sc with CPZ (5 mg/kg), DTE (80 mg/kg), or saline (controls). CPZ and DTE significantly depressed the rectal temperature to 32.8 and 34.5 degrees C, respectively. One hour later, all three groups received a specified dose of ethanol (6.5-10.7 g/kg, 24% w/v, intraperitoneal). The experiment was repeated 17 times at different ethanol doses. The pretreatments increased the 1 hr LD50 from 7.8 +/- 0.1 g/kg for the controls to 8.6 +/- 0.2 g/kg (DTE) and 10.0 +/- 0.3 g/kg (CPZ) (p less than 0.001). The protective effect of CPZ was maximal around 5 mg/kg, and less at both lower and higher CPZ doses. When the temperature drop was prevented by directly heating the mice, the protective effect of DTE could be eliminated, but the effect of CPZ was only partially prevented. Placing the CPZ-treated mice in a warmer environment only produced a major reversal of CPZ protection when rectal temperature reached 38 degrees C. In conclusion, CPZ and DTE both decrease body temperature and protect against acute ethanol toxicity. The protection seems to be due at least partially to the decrease in body temperature prior to ethanol injection.

Efficiency of hydrogen photoproduction by photosystem I-enriched subchloroplast vesicles combined with Proteus mirabilis cells. Effects of some exogenous electron donors

High rates of hydrogen photoproduction are obtained when glutaraldehyde-fixed Photosystem I-enriched vesicles (Photosystem II-depleted) are added to hydrogenase-containing cells of Proteus mirabilis in the presence of the mediator methylviologen and a suitable electron donating system. This donor system includes ascorbate, dithioerythritol (DTE) and the mediator tetramethylphenylene-diamine (TMPD) and reduces the photosynthetic electron transfer chain at the level of plastocyanin. Both DTE and ascorbate are required for hydrogen photoproduction, DTE being the ultimate electron donor and ascorbate only having a catalytic function. Whereas the aerobic photoreduction of methylviologen is similar in the presence of DTE, ascorbate or both, under anaerobic conditions only combination of both compounds results in a high and stable amount of reduced methylviologen that can be utilized by the hydrogenase. It is concluded that oxidation reactions of reduced methylviologen, competing with the hydrogenase, rather than methylviologen photoreduction, limit hydrogen photoproduction in the presence of either DTE or ascorbate. These oxidation reactions are suggested to involve back reactions to the oxidized form(s) of ascorbate and DTE but backflow to the photosynthetic electron transfer chain (i.e. cyclic electron transfer) can not be excluded.

Formation of Elemental Sulfur by Chlorella fusca during Growth on l-Cysteine Ethylester

During growth on l-cysteine ethylester, Chlorella fusca (211-8b) accumulated a substance which contained bound sulfide, which could be liberated by reduction with dithioerythritol (DTE) as inorganic sulfide. This substance was extracted with hot methanol and purified by thin layer chromatography. This substance liberated free sulfide when incubated with mono- and dithiols, and thiocyanate was formed after heating with KCN. The isolated substance cochromatographed with authentic sulfur flower using different solvent systems for thin layer chromatography, high pressure liquid chromatography, and the identical spectrum with a relative lambda(max) at 263 nm was found. The chemical structure was confirmed by mass spectrometry showing a molecular weight of 256 m/e for the S(8) configuration. No labeled elemental sulfur was detected when the cells were grown on [(35)S]sulfate and l-cysteine ethylester indicating the origin of elemental sulfur from l-cysteine ethylester. C. fusca seems to have enzymes for the metabolism of elemental sulfur, since it disappeared after prolonged growth into the stationary phase. Cysteine was formed from O-acetyl-l-serine and elemental sulfur in the presence of thiol groups and purified cysteine synthase from spinach or Chlorella.

Properties of latent and thiol-activated rat hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase and regulation of enzyme activity

The effect of the thiols glutathione (GSH), dithiothreitol (DTT), and dithioerythritol (DTE) on the conversion of an inactive, latent form (E 1) of rat liver 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase, EC 1.1.1.34) to a catalyticaly active form (E a) is examined. Latent hepatic microsomal HMG-CoA reductase is activated to a similar degree of activation by DTT and DTE and to a lower extent by GSH. All three thiols affect both K m and V max values of the enzyme toward HMG-CoA and NADPH. Studies of the effect of DTT on the affinity binding of HMG-CoA reductase to agarose-hexane-HMG-CoA (AG-HMG-CoA) resin shows that thiols are necessary for the binding of the enzyme to the resin. Removal of DTT from AG-HMG-CoA-bound soluble E a (active enzyme) does not cause dissociation of the enzyme from the resin at low salt concentrations. Substitution of DTT by NADPH does not promote binding of soluble E 1 (latent enzyme) to AG-HMG-CoA. The enzymatic activity of E a in the presence of DTT and GSH indicates that these thiols compete for the same binding site on the enzyme. Diethylene glycol disulfide (ESSE) and glutathione disulfide (GSSG) inhibit the activity of E a. ESSE is more effective for the inhibition of E a than GSSG, causing a higher degree of maximal inhibition and affecting the enzymatic activity at lower concentrations. A method is described for the rapid conversion of soluble purified E a to E 1 using gel-filtration chromatography on Bio-Gel P-4 columns. These combined results point to the importance of the thiol/disulfide ratio for the modulation of hepatic HMG-CoA reductase activity.

Structural requirements of rabbit IgG F(ab') 2 fragment for activation of the complement system through the alternative pathway—I. Disulfide bonds

Selective carboxymethylation of disulfide bonds of the F(ab') 2 fragment from rabbit IgG was performed in order to study its possible implication in the activation of the complement system by the alternative pathway. Disulfide bonds were selectively modified by reduction with different amounts of dithioerythritol (DTE)† followed by alkylation with iodoacetamide. Monovalent fragments of antibody to sheep erythrocytes, obtained after reduction and carboxymethylation, were capable of mediating the lysis of sheep erythrocytes by the alternative pathway. The chemical modification did not alter the conformational integrity of the protein as shown by CD spectra. These monovolent fragments were as efficient as the bivalent fragment when the results were normalized taking into account the loss of antibody avidity observed in the monovalent antibodies with respect to the bivalent ones. The Fab fragment, obtained by papain digestion, exhibited a similar behaviour to the Fab' fragment. This suggests that the C2-oligosaccharide present in the hinge region of the antibody molecule is not involved in the complement activation through the alternative pathway. These data may suggest that the inter-chain disulfide bonds are not involved in maintaining the effector structures required for complement activation through the alternative pathway.

Carbohydrate in contrast to protein feeding increases the hepatic content of active thyroxine-5'-deiodinase in the rat.

Dietary constituents have specific effects on serum T3 and rT3 concentrations. We have previously demonstrated that glucose- compared to protein-fed rats have higher serum T3 levels. These alterations reflected greater hepatic T4- 5′-deiodinase activity in the glucose-fed group. To determine whether the greater enzyme activity was consequent to an increase in the hepatic content of active enzyme or sulfhydryl cofactor, further studies on T4-deiodination have been performed in liver homogenate preparations from glucose (20% glucose in water) and Purina (25% protein)-fed rats compared to 72-h fasted rats treated with L-T4. The Purina-fed animals demonstrated greater (P < 0.01) T4- 5′-deiodinase activity (T4 to T3) than the 72-h fasted group. However, hepatic T4-5-deiodinase activity (T4 to rT3) was similar for these dietary groups. Homogenate enrichment with the thiol reagent dithioerythritol (DTE) reversed the difference noted between the Purina-fed and the fasted group. Moreover, the hepatic content of no...

Effect of thiols on macroconidia of Fusarium sulphureum.

Treatment of Fusarium sulphureum macroconidial cells with five thiols alters their morphology. Macroconidial cells incubated in dithiothreitol (DTT), dithioerythritol (DTE), or thiourea differentiate into thick-walled, chlamydospore-like cells (thiol-induced spores). These cells appear similar in size and shape to chlamydospores in the light microscope, but differ markedly in cell wall structure when viewed in the electron microscope (EM). Incubation of macroconidia with both DTT and DTE also leads to the formation of large swollen cells (giant cells) which have a parietal cytoplasm and electron-tranparent cell walls; most of these giant cells lyse within 3 to 7 days of incubation. Thiourea-induced spores are characterized by the deposition of a thick, electron-dense, extracellular layer and an accumulation of mitochondria. DTT and DTE, at the concentrations used, inhibit macroconidial germination while thiourea, mercaptoethanol, and cysteine do not. With the latter three thiols, the newly formed hyphal cells become elongated with either one or both ends swollen. Mercaptoethanol-treated cells contain an abundance of mitochondria. The DTT-induced spore differs from both macroconidia and chlamydospores with respect to cellular lipid and cell wall composition. While the thiols have different effects on the macroconidia, the fact that they all induce cell expansion suggests that they react at some common sites.

Characterization of the calcium-induced disruption of neurofilaments in rat peripheral nerve

Transverse frozen sections of desheathed rat peripheral nerve were incubated in media of different composition prior to fixation and processing for electron microscopic examination. Neurofilaments remained intact when these tissues were incubated in calcium-free media. A loss of neurofilaments and their replacement by granular debris occurred in myelinated and unmyelinated fibers following incubation in media containing 2 mM calcium. The calcium-mediated disruption of neurofilaments was inhibited by preincubation or incubation with 1 mM p-chloromercuribenzoate (PCMB). The inhibition by preincubation with PCMB could be partially reversed by subsequent preincubation with 10 mM dithioerythritol (DTE). Calcium-mediated breakdown of neurofilaments did not occur after prolonged preincubation in calcium-free media, a finding which suggested that neurofilament disruption was dependent upon a tissue which could be lost or inactivated in frozen-sectioned nerve tissues. The findings of the present study provide morphological evidence that neurofilament disruption in mammalian peripheral nerve is mediated by a calcium-activated, PCMB-sensitive enzyme in the axoplasm of myelinated and unmyelinated nerve fibers.

Localization of [formula omitted] sulfhydrylase in Spinacia oleracea L.

Roots and hypocotyls of 11 day-old spinach seedlings with fully developed cotyledons contained 30–35% of the total O- acetyl-L- serine sulfhydrylase (OASSase) extractable from the plants. After centrifugation of homogenates from roots on sucrose density gradients, OASSase activity was present in the fractions containing the proplastids. In leaf extract two forms of OASSase could be detected by polyacrylamide disc gel electrophoresis. The form with the lower electrophoretic mobility in 0.1 M Tris-glycine at pH 8.4 could be attributed to the chloroplasts. The chloroplast enzyme was less stable than the extrachloroplastic form if stored without dithioerythritol (DTE).

Morphological changes induced by -SH reagents in rod photoreceptor outer segments.

Rat retinas were treated in vitro with -SH reagents and "stained" with zinc iodide-osmium tetroxide (ZIO). Dithioerythritol (DTE), an -S-S-reducing agent, increased the electron opaque deposits observed after ZIO staining in the intra- and extradiskal spaces of the rods. N-ethyl-maleimide (nem), an -SH blocking agent, applied directly or after DTE, blocks the ZIO reaction. Furthermore, after treatment with NEM, distorted tubular and vesicular structures are substituted for the stacks of disks. These results strongly suggest that ZIO reacts with -SH groups in rod outer segments. They also indicate that SH-groups play an important role in the structural organization of rod outer segments.

The adenosine-5?-phosphosulfate sulfotransferase from spinach (Spinacea oleracea L.). Stabilization, partial purification, and properties

Adenosine-5'-phosphosulfate (APS) sulfotransferase was purified 25-fold from spinach (Spinacea oleracea L.) leaves by Sephadex-G-200 gel filtration and chromatography on DEAE-cellulose. Enzyme activity was stabilized with 0.05 M Tris-HCl pH 8.0 containing 10 mM mercaptoethanol (ME), 10 mM MgCl2, and 30% glycerol. The molecular weight of the APS-sulfotransferase was estimated by gel filtration to be about 110,000 daltons. The enzyme is specific for the sulfonucleotide APS; PAPS is not a sulfur donor for this reaction. The apparent Km for APS was found to be 13 μM. The enzyme activity was determined with dithioerythritol (DTE) as acceptor, which has an apparent Km of 0.6 mM. Glutathione can substitute for DTE; other thiols such as mercaptoethanol and cysteine are less effective. The APS-sulfotransferase activity is inhibited by 5'-AMP, which increases the Km for APS but does not change Vmax, suggesting a competetive inhibition. Reduced methylviologen cannot substitute for a thiol in the spinach enzyme system. Thus it seems that assimilatory APS-sulfotransferase from spinach is different from the dissimilatory APS-reductase from Desulfovibrio or Thiobacillus, where methylviologen can be used as the electron donor.

58] Glyceraldehyde-3-phosphate dehydrogenase from rabbit muscle

This chapter describes the assay method, purification procedure, and properties of glyceraldehyde-3-phosphate dehydrogenase from rabbit muscle. The enzyme is assayed spectrophotometrically at 340 nm by the method of Krebs except that Tris buffer is substituted for the pyrophosphate buffer. All steps in the purification scheme are carried out at 0–4°. In order to minimize the inactivating effects of heavy metal ions, the saturated ammonium sulfate solutions should be prepared with enzyme grade reagent. In addition, EDTA, KCN, and dithioerythritol (DTE) or dithiothreitol (DTT) are used throughout purification to protect the sulfhydryl groups of the enzyme. The percent saturation of the ammonium sulfate solutions is calculated by the formula of Kunitz. The pH of the ammonium sulfate solutions is determined with a pH meter after diluting 1:20. After specific inhibition of the rabbit muscle enzyme with [1- 14 C] iodoacetic acid and tryptic digestion, a single radioactive peptide is obtained, which contains [1-C 14 ]carboxymethylcysteine. The amino acid sequence of the “active-site” peptide is similar to those of the enzyme isolated from other sources.

Creatine kinase reactivation by thiol compounds

It is now commonly accepted that thiol activated creatine kinase (CK) assay systems measure CK activity more accurately and more reproducibly than non-activated systems. However, some differences have arisen in the literature in regards to the nature and course of CK activation. Some thiol compounds have been reported to yield higher enzyme activities than others. Dalal et al. (1) reported that mercaptoethanol at 6.5 mM is suboptimal in the Siegel and Cohen assay (2); whereas, dithiothreitol (DTT) at 4 mM yields maximum activity. Warren has shown that DTT and mercaptoethanol produce significantly greater CK activities than cysteine, dithioerythritol (DTE), glutathione, or mercaptoacetate (3). Bishop et al. (4) and Kar and Pearson (5) reported that CK was equally activated independent of the thiol activator. We report here our findings on the relative effectiveness of mercaptoethanol, cysteine, glutathione, and DTT in the reactivation of serum CK using the Oliver-Rosalki method (6,7) and some characteristics of the reaction process.

Ehrlich ascites cells DNA-dependent RNA polymerases: Effect of amino acids protein synthesis inhibition

FEBS LettersVolume 41, Issue 1 p. 161-165 Full-length articleFree Access Ehrlich ascites cells DNA-dependent RNA polymerases: Effect of amino acids protein synthesis inhibition Silvia Cereghini, Silvia Cereghini Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires, ArgentinaSearch for more papers by this authorMaría T. Franze-Fernández, María T. Franze-Fernández Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires, ArgentinaSearch for more papers by this author Silvia Cereghini, Silvia Cereghini Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires, ArgentinaSearch for more papers by this authorMaría T. Franze-Fernández, María T. Franze-Fernández Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires, ArgentinaSearch for more papers by this author First published: April 15, 1974 https://doi.org/10.1016/0014-5793(74)80978-6Citations: 18AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL References 1 J.R. Tata, Prog. Nucl. Acid Res. Mol. Biol., 5, (1966), 191– 250. 2 M.T. Franze-Fernández, A.O. Pogo, Proc. Natl. Acad. Sci. U.S., 68, (1971), 3040– 3044. 3 M.T. Franze-Fernández, A.V. Fontanive-Sanguesa, Biochim. Biophys. Acta, 331, (1973), 71– 80. 4 R.G. Roeder, W.J. Rutter, Proc. Natl. Acad. Sci. U.S., 65, (1970), 675– 682. 5 T.J. Lindell, F. Weiberg, P.W. Morris, R.G. Roeder, W.J. Rutter, Science, 170, (1970), 447– 449. 6 P. Chambon, F. Gissinger, J.L. Mandel, C. Kedinger, M. Gniazdowski, M. Meihlac, Cold Spring Harbor Symp. Quant. Biol., XXXV, (1970), 693– 707. 7 S.P. Blatti, C.J. Ingles, T.J. Lindell, P.W. Morris, R.F. Weaver, F. Weinberg, W.J. Rutter, Cold Spring Harbor Symp. Quant. Biol., XXXV, (1970), 649– 657. 8 B. Sugden, W. Keller, J. Biol. Chem., 248, (1973), 3777– 3788. 9 D.G.R. Blair, M. Dommasch, Biochem. Biophys. Res. Commun., 49, (1972), 877– 883. 10 E.A. Peterson, T.S. Work E. Work Cellulosic Ion Exchangers (1970), North-Holland Amsterdam 262– 11 L.R. Versteegh, C. Warner, Biochem. Biophys. Res. Commun., 53, (1973), 838– 844. 12 C. Kedinger, F. Gissinger, M. Gniazdowski, J.L. Mandel, P. Chambon, Eur. J. Biochem., 28, (1972), 269– 276. 13 F.L. Yu, P. Feigelson, Proc. Natl. Acad. Sci. U.S., 69, (1972), 2833– 2837. 14 B.J. Benecke, A. Ferencz, K.H. Seifart, FEBS Letters, 31, (1973), 53– 58. 15 Gross, K. J. and Pogo, A. O. J. Biol. Chem. (in press). Citing Literature Volume41, Issue1April 15, 1974Pages 161-165 ReferencesRelatedInformation

Characterization of Sofffi Metaltion Dithiothreitolates and Dithioerythriotoilates

Abstract Cadmium, lead and zinc ions have been shown to form precipitates with dithiothreitol (DTT) and dithioerythritol (DTE)(threo and erythro isomers of 2,3-dihydroxy-l, 4-dithiobutane). The solubility products for these compounds have been determined polarographically. The Ksp values at 23° in 0.1 M KCL for CdDTT, CdDTE, PbDTT and ZnDTE have been found to be 6.3 × 10-21, 1.1 × 1019, 7.0 × 10−18 and 2.7 × 1015 respectively. Evidence is presented for the presence of a 1:1 stoichiometry for these compounds.