Cysteine Ethyl Ester Research Articles

Polarographic catalytic hydrogen currents in the presence of various thiols

The polarographic catalytic hydrogen current (Brdicka's current) was studied in the buffered solutions of various thiols containing Co(II) ions. It was found that the catalytic activity of structurally similar thiols decreases with the decreasing values of the stability constants of their complexes with Co(II) ions following the order: cysteine ethyl ester>cysteine >cysteamine or mercaptosuccinic acid>thioglycollic acid>2-mercaptopropionic acid. 2-diethylaminoethanethiol and S-ethylcysteine were fully inactive. The explanation of the observed phenomena was suggested.

Partial purification and properties of S-cysteinyl-hydroxychlorpropham transferase from oat ( Avena sativa L.)

S-Cysteinyl and glutathione conjugates of isopropyl-3′-chloro-4′-hydroxycarbanilate (4-hydroxychlorpropham) were synthesized directly in the presence of soluble enzyme systems isolated from etiolated shoots of oat seedlings. The enzyme systems responsible for these reactions were partially purified and charaterized. Enzyme A appeared to be a multicomponent system, equally reactive with either cysteine or glutathione. Enzyme B was twice as active as enzyme A in the formation of S-cysteinyl-hydroxychlorpropham. Affinity chromatography of enzyme A produced an enzyme fraction with properties similar to those of enzyme B. Both enzymes (A and B) were significantly inhibited by increased cysteine concentrations. The reaction of glutathione with enzyme B was limited. However, when low concentrations of a nonreacting effector, cysteine ethyl ether, were added, glutathione conjugation increased significantly. At higher concentrations, cysteine ethyl ester formed a conjugate with 4-hydroxychlorpropham. Isopropyl-5′-chloro-2′-hydroxycarbanilate (2-hydroxy-5-chlorpropham) did not conjugate with either cysteine or glutathione but did react with cysteine ethyl ester. Isopropyl-3′-chlorocarbanilate (chlorpropham) was not a substrate for thioether conjugation. These data suggest that para- and/or ortho-hydroxylated carbanilates and cysteine-related substrates may form thioether conjugates when incubated under appropriate conditions with these complex enzyme systems.

S-cysteinyl-hydroxychlorpropham transferase inhibition by chlorpropham analogs, sulfhydryl compounds, ortho- and/or para-substituted phenols, and firefly luciferin

Inhibition of S-cysteinyl-hydroxychlorpropham transferase from oat ( Avena sativa L.) by various compounds was studied. The β- O-glucoside of the substrate, isopropyl-3′-chloro-4′-hydroxycarbanilate (4-hydroxychlorpropham), and isopropyl-3′-chlorocarbanilate (chlorpropham) did not inhibit the enzyme. Isopropyl-5′-chloro-2′-hydroxycarbanilate (2-hydroxy-5-chlorpropham), was a competitive inhibitor with respect to 4-hydroxychlorpropham, but 2-β- O-glucosyl-5-chlorpropham was not an inhibitor. The inhibition patterns exhibited by 2-hydroxy-5-chlorpropham and other aryl-hydroxylated analogs suggested that the site of aryl-cysteine thioether conjugation might be the ortho (2′) aromatic carbon. Inhibitions by 3-chloro-4-hydroxyaniline and ferulic acid suggest that related phenols and/or naturally occurring phenolic plant acids could serve as substrates for the enzyme system. Glutathione was a competitive inhibitor with respect to cysteine and could also form a conjugate with 4-hydroxychlorpropham. Atypical inhibitions of cysteine conjugation by cysteine ethyl ester or firefly d-luciferin were described. Similarities between S-cysteinyl-hydroxychlorpropham transferase and firefly luciferase were noted.

The new polarographic current of the catalytic evolution of hydrogen in a buffered system containing a thiol and cobalt(II) ions

A new polarographic current, caused by the catalytic evolution of hydrogen, has been observed on a hanging mercury drop electrode at a potential of about −1.3 V (SCE). This current appears in solutions containing 0.1 M NH 4 Cl, 0.1 M NH 3 , 0.001 M CoCl 2 and a thiol such as mercaptosuccinic, thioglycolic, 2-mercaptopropionic, thioacetic or thiosalicylic acid, cysteamine, 2-diethylaminoethanethiol, cysteine ethyl ester or 2-mercaptoethanol. The appearance of this current depends on the electrolytic formation of a solid cobalt deposit on the electrode, leading to a lower hydrogen overvoltage than on mercury. The deposit is formed in the simultaneous presence of cobalt(II) ions and a thiol in the narrow potential range and its growth is inhibited by gelatin.

The new polarographic current of the catalytic evolution of hydrogen in a buffered system containing a thiol and cobalt(II) ions

A new polarographic current, caused by the catalytic evolution of hydrogen, has been observed on a hanging mercury drop electrode at a potential of about −1.3 V (SCE). This current appears in solutions containing 0.1 M NH 4Cl, 0.1 M NH 3, 0.001 M CoCl 2 and a thiol such as mercaptosuccinic, thioglycolic, 2-mercaptopropionic, thioacetic or thiosalicylic acid, cysteamine, 2-diethylaminoethanethiol, cysteine ethyl ester or 2-mercaptoethanol. The appearance of this current depends on the electrolytic formation of a solid cobalt deposit on the electrode, leading to a lower hydrogen overvoltage than on mercury. The deposit is formed in the simultaneous presence of cobalt(II) ions and a thiol in the narrow potential range and its growth is inhibited by gelatin.

Novel octahedral complexes of nickel(II) with thioether derivatives of cysteine ethyl ester

Novel octahedral complexes of nickel(II) with thioether derivatives of cysteine ethyl ester

Studies with alkylating esters VI. The chemical and biological activities of the isomers of dimethylmyleran

The meso- and (±)-isomers of dimethylmyleran (DMM) have been synthesised and their chemical reactivity towards selected nucleophiles has been investigated. Both isomers react in vitro by hydrolysis to give 2,5-dimethyltetrahydrofuran and with the thiol groups of cysteine, cysteine ethyl ester and glutathione forming 2,5-dimethyltetrahydrothiophene. As each of these cyclic compounds exists in the cis- and trans-configurations, their production in stereochemically quantitative yields from meso- and (±)-dimethylmyleran respectively, indicates that both isomers react by a bimolecular process and not a unimolecular one as has been generally accepted. A comparison of the activity of the isomers with that of Myleran on anti-fertility action, neutrophildepressant activity and effect on the weight response suggests that these esters could exert their biological actions in vivo by the same mechanism.

A reinvestigation of the reaction of [formula omitted]-benzoquinone with cysteine ethyl ester: revision of a structural assignment

A reinvestigation of the reaction of [formula omitted]-benzoquinone with cysteine ethyl ester: revision of a structural assignment

Chlorinolysis of cysteine ethyl ester hydrochloride: an efficient route to certain chloro-amino acid derivatives

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChlorinolysis of cysteine ethyl ester hydrochloride: an efficient route to certain chloro-amino acid derivativesB. E. Norcross and R. L. MartinCite this: J. Org. Chem. 1969, 34, 11, 3703–3705Publication Date (Print):November 1, 1969Publication History Published online1 May 2002Published inissue 1 November 1969https://doi.org/10.1021/jo01263a133RIGHTS & PERMISSIONSArticle Views66Altmetric-Citations5LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (393 KB) Get e-Alerts Get e-Alerts

The Enzymatic Oxidation of Cysteamine to Hypotaurine: PURIFICATION AND PROPERTIES OF THE ENZYME

The enzyme oxidizing cysteamine to hypotaurine has been extracted from horse kidney and purified. The final product behaves as a single protein when analyzed in the ultracentrifuge, by starch gel electrophoresis, and by filtration on dextran gels. The sedimentation coefficient of the pure product is s20, w = 5.9. The molecular weight determined by the Yphantis procedure (22) is 83,000. Nonheme iron is contained in the amount of 1 atom per molecule of enzyme. Spectrophoto-metric analyses indicate absence of nonprotein chromophores in the visible and in the near ultraviolet range. The complete amino acid composition has been determined by ion exchange chromatography. The effect of sulfide, methylene blue, and hydroxylamine, which act as cofactor-like compounds, has been studied. Of the substrates assayed (cysteamine, cysteine, cysteine ethyl and methyl esters, and reduced glutathione), only cysteamine is oxidized to the sulfinic derivative in the presence of the cofactor-like compounds named.

Interaction between myosin and its substrates

Low concentrations of p-chloromercuribenzoate (PCMB), Zn ++, or Cd ++ increase the ATPase and CTPase activities of myosin B but inhibit ITPase and GTPase activities. Higher concentrations of these modifiers inhibit the activities of all the nucleoside triphosphates (NTP). Dialysis against cysteine ethyl ester (CEE) increases the ATPase and CTPase activities of myosin but decreases the ITPase and GTPase activities. The temperature dependence of the maximum velocities of hydrolysis and of the Michaelis-Menten constants also differentiate between ATP-CTP and ITP-GTP. ATP and CTP confer considerable protection against thermal denaturation of myosin, while ITP and GTP confer only a small protection. The shape of the PCMB vs. NTPase activity curve is invariant to the substitution of Mg ++ for Ca ++ in the presence of 0.3 M KCl or to the substitution of Na +, Li +, or NH 4 + for K + in the presence of Ca ++. PCMB inactivates myosin at 37 ° at a rate which is highly sensitive to the PCMB concentration. The inactivated myosin can be restored to activity by dialysis against CEE. These and other observations are interpreted in terms of a conformation change at the active site of myosin.

The effect of certain sulfur compounds on the myosin B-ATP system

1. 1. Exposure of myosin (B) ATPase to 0.01 − 0.001 M cysteine ethyl ester or S-β-aminoethylisothiuronium in mildly alkaline solution, followed by “washing out” of the sulfur compounds, converts the ATPase into a state wherein it is markedly more responsive to Ca ++ activation than protein not so treated. 2. 2. The v m (pH) relation of protein so treated resembles a simple titration curve, and, in particular, it appears to lose the velocity maximum at pH 6.4 which is characteristic of untreated protein. 3. 3. The intensity of light scattered from a freshly prepared dilution of myosin (B) decays markedly over the subsequent hours, as does the magnitude of the intensity drop evoked by ATP addition. The presence of 0.001 M S-β-aminoethylisothiuronium moderately accelerates these decays.