Cysteine Sulphinic Acid Research Articles

Amino acids in the synaptic vesicle fraction from calf brain: content, uptake and metabolism

A synaptic vesicle fraction was prepared from calf brain cortex, containing 10 identified amino acids and two unidentified ninhydrin-positive compounds, one of which is apparently a peptide. The most plentiful amino acids were taurine (1.8 nmol/g original tissue), glutamic acid (1.8), serine (0.9), aspartic acid (0.8) and GABA (0.8); the others identified were cysteic acid (or cysteinesulphinic acid), glutamine, alanine, glycine and lysine. The unknown peptide occurred in a high concentration (about 16 alanine equivalents/g), and contained mainly aspartic acid and serine. Cysteic acid (or cysteinesulphinic acid) also occurred in relatively high amounts, but its peak contained acid-labile impurities. The influx of [14C]glutamate into the vesicles took place by means of non-saturable migration, while two saturable systems having very similar properties were dominant only at low glutamate concentrations. Influx constants for these quantitatively low uptake systems were Km, 34 and 92 micrometer, and Vmax, 33 and 49 nmol/min/g obtained by v versus v/S plot. Almost the same values were also obtained by a 1/v versus 1/S plot. GAD and GABA-T activities in the vesicles were only 1/200th of those in the synaptosomes.

Subcellular distribution of enzymes of transmethylation and transsulphuration in rat brain.

Abstract—Certain of the sulphur containing amino acids have been associated with synaptic transmission in the central nervous system. The enzymes involved in the synthesis of these putative neurotransmitter or modulator compounds have a different subcellular distribution in rat brain from those enzymes that catalyse the synthesis of other compounds in this pathway. Methionine adenosyltransferase and 5‐methyltetrahydrofolate‐homocysteine methyltransferase catalyse reactions that maintain the methylation functions of the pathway and are found in soluble fractions. Cystathionine β‐synthase, cystathionase, cysteine dioxygenase and cysteine sulphinic acid decarboxylase catalyse the synthesis of those sulphur‐containing amino acids implicated in neurotransmitter functions and these enzymes have both paniculate and soluble components. Serine hydroxymethyltransferase, which also has a particulate fraction in brain, is responsible for the synthesis of the neurotransmitter glycine, in addition to its role in the methionine‐related metabolism of folate.

60Co-gamma radiolysis of cysteine in aerated and oxygen saturated in perchloric acid solutions

Abstract Gamma radiolysis of cysteine in aerated and oxygen saturated acidic solutions leads to a chain decomposition of the solute with a corresponding formation of cystine and cysteine sulphinic acid. A reaction mechanism to explain the experimental yields is proposed and a rate expression for G(-CySH) evaluated. It is found that the calculated and experimental G(-CySH) are in excellent agreement. It is also found that G(CyS-SCy) and G(H202) increase with decreasing dose rate (I). G(Cys-SCy) and G(H2O2) plotted against I/✓I are straight lines suggesting a radical-radical chain termination step.

Proton magnetic resonance spectra of amino-acids and peptides relevant to wool structure. Part II. Relative residence times of sulphur-containing α-amino-acids

High resolution 1H n.m.r. spectra at 60 MHz of alkaline deuterium oxide solutions of eight sulphur-containing amino-acids have been examined over the temperature range 280–355 K. Iterative analyses of the ABC spin systems of the methylene and methine resonances yield coupling constants from which apparent fractional populations of the individual rotamers have been calculated. For djenkolic acid there is a slight tendency for equalization of population with increase in temperature; for cysteine sulphinic acid and, to a small extent, S-carboxymethyl-cysteine, the dominance of one or two rotamers increases with temperature; for lanthionine, cysteine, and S-benzylcysteine, the relative lifetimes of the three rotamers are almost unchanged; while in the case of S-methyl- and S-allyl-cysteine, the dominant rotamers alter with temperature. For six sulphur-containing amino-acids examined in acidic solution at 303 K, the coupling constants derived are remarkably consistent; the geminal coupling, JAB, is ca. –15·0 Hz (modulus about 2 Hz larger than for alkaline solution), and the vicinal couplings, JAC and JBC, are ca. 7·9 and 4·4 Hz, respectively.

Formation and excretion of taurine in x-irradiated rats.

SummaryUrinary excretion profiles of taurine have been estimated in male Wistar rats exposed to doses of x-rays ranging from 100–1000 R. Maximum levels were observed in urine collected 24 hours after irradiation. Urinary taurine returned to normal values within 48 hours only in rats which had received sublethal doses (100–400 R). The high taurine levels persisted even after 72 hours in rats receiving more than LD50, i.e. 600–1000 R. The dose–response relationship obtained indicates a sort of a threshold dose beyond which the recovery mechanisms apparently do not operate.Urinary excess of taurine could be ascribed to enhanced liver cysteic acid decarboxylase activity. The increase in enzyme activity corresponds to the maximum appearance of taurine in the urine. Cysteine sulphinic acid decarboxylase did not show any variation.Formation of taurine in vivo was also followed up after intraperitoneal injection of cysteine-3-14C. There was enhanced recovery of radioactivity of the injected amino acid in blood and urine of x-irradiated animals, indicating increased synthesis of taurine. Hypertaurinuria could be prevented by prior treatment with desoxypyridoxine.

Activities of cystathionase, cysteine sulphinic acid decarboxylase and serine dehydrase in the liver of tumour-bearing rats.

Dans le foie de rats porteurs de tumeurs (epitheliome de Guerin et sarcome de l'estomac), les activites de la cystathionase, de la decarboxylase de l'acide cysteine sulfinique et de la serine dehydrase sont considerablement diminuees: cette diminution est de l'ordre de 50%, 15 jours apres implantation de ces tumeurs. Si a ce moment le sarcome (qui ne provoque pas de metastases) est chirurgicalement extirpe, on observe une restauration des activites enzymatiques qui, apres 15 jours, est totale pour la cystathionase et tres significative pour la decarboxylase.

Effects of puromycin and actinomycin D on the increase of cystathionase and cysteine sulphinic acid decarboxylase activities in the liver of thyroidectomized rat.

PREVIOUS investigations carried out in this laboratory have shown that the concentration of two cytoplasmic rat liver enzymes dependent on pyridoxal phosphate, namely, cysteine sulphinic acid (CSA) decarboxylase (L. cysteine sulphinate carboxylase E.C. 4.1.1.29) and cystathionase (L. homoserine hydrolyase E.C. 4.2.1.15), are adaptively increased in thyroidectomized animals1,2. The events underlying these changes in response to thyroidectomy are not known; however, we have suggested that the increase of activities may be attributable to an increased biosynthesis of the two apoenzymes3, and recently we have obtained results which agree with such a hypothesis4. The experiments reported here were undertaken in order to determine whether these increases are prevented by injections of inhibitors of protein biosynthesis—puromycin5—and of the DNA-directed RNA synthesis—actinomycin D (ref. 6). Both experiments were carried out in similar conditions except that in the first rats were given intraperitoneal injections of puromycin daily for 4 days at a dose each of 5 mg/100 g of body weight, whereas in the second actinomycin D was injected by the same route and for the same time at a dose of 3 µg/100 g of body weight. The animals were killed 4 h after the last injection. The amounts of inhibitor injected were chosen taking into consideration the report of Weber et al.7 and the results of preliminary assays.

COMPARISON OF DECARBOXYLATION OF CYSTEINE SULPHINIC ACID-1-14C AND CYSTEIC ACID-1-14C BY HUMAN, DOG, AND RAT LIVER AND BRAIN.

CYSTEINE sulphinic acid (CSA) is an intermediary product in the conversion of cysteine to taurine in the rat1. Cysteic acid (CA) has also been shown to be a precursor of taurine in the rat2. CSA and, to a lesser extent, CA increase the production of carbon dioxide by liver and brain tissue from some mammalian species (the rat3, the rabbit4, and the dog5), although not from others (the horse5 and the cat6). These findings indicate that the formation of taurine in some mammalian species may proceed along the pathways shown in Fig. 1.

Cysteine biosynthesis in beet discs

The incorporation of [ 35S] sulphate into cysteine by discs of red beetroot has been studied, and the amino acid isolated by adding N-ethyl maleimide to the ethanolic extracting solution and subsequent paper chromatography of the N-ethyl maleimide–cysteine adduct. The addition of L-serine (1–10mM) to beet discs that have been washed in aerated water to lower their endogenous pools of amino acids caused an increase (maximum observed 80–90 per cent) in the incorporation of radioactivity from [ 35S] sulphate into cysteine. D-Serine and glycine do not have this effect; in fact D-serine inhibits the uptake of sulphate by the tissue. The discs convert L-[ 14C] serine to [ 14C] cysteine. No [ 35S] cysteine sulphinic acid was detected after feeding with [ 35S] sulphate.

Étude polarographique de la désulfination de l'acide cystéinesulfinique par des extraits de feulles d'avoine

The rate of sulphite formation in the presence of cysteinesulphinic acid, of an α-ketonic compound and of a protein extract of oat leaves was measured by polarography. The velocity of sulphite formation represents the rate of transmination of the cysteinesulphinic acid. This transamination, which can occur either with α-ketonglutaric acid or with oxalacetic acid, has an optimum pH of about 8 in phosphate buffer, and the catalysing enzyme in activated by pyridoxal phosphate. Malic acid behaves as a competitive inhibitor for cysteinesulphinic acid in respect of the transaminase studied.

THE SUCCINIC OXIDASE ACTIVITY OF RAT LIVER MITOCHONDRIA

Rat liver mitochondria diluted into a high-potassium phosphate-free medium containing 2 × 10−5 M DNP take up oxygen readily if succinate is added at the same time as the mitochondria. If the addition of succinate is delayed, the respiration elicited is markedly reduced, falling to about 5% of the zero-time control at 2 minutes. Succinate-linked respiration can be restored by the addition of ATP or of cysteine sulphinic acid. A spontaneous recovery occurs on prolonged incubation (> 20 minutes). The inactivation, at least at such short incubation times, is dependent on the presence of DNP, and partial protection is provided by inorganic phosphate and the substitution of sucrose for KCl. Considerable protection is also provided by the presence of 1.5 mM Amytal. These results are all consistent with the hypothesis that oxaloacetate is produced from endogenous substrate during the first 1 or 2 minutes after dilution of the mitochondria, and that the failure to demonstrate succinic oxidase activity after this time is due to the inhibition of succinic dehydrogenase by oxaloacetate.

Studies on isolated human skeletal muscle mitochondria

Mitochondria prepared from human skeletal muscle tissue have been analyzed for oxidation rates with different substrates, P O ratios, ATPase activities, P i-ATP exchange rates and respiratory control ratios. Human skeletal muscle mitochondria oxidize at high rates pyruvate (+malate), α-ketoglutarate and glutamate, and at lower rates all other Krebs cycle metabolites, glycerol-1-phosphate and fatty acids. The oxidation rate of succinate is increased several times if oxaloacetate is removed from the medium by the addition of cysteine sulphinic acid, or if its formation is prevented by the addition of amytal. Adequate P O ratios are obtained with most substrates tested. Addition of 2,4-dinitrophenol (DNP) causes an inhibition of the oxidation of glutamate, but not of α-ketoglutarate, and the inhibition goes parallel to the uncoupling effect. Addition of adenine nucleotides partially protects against the inhibition of glutamate oxidation. Complete abolishment of respiratory control is obtained with 10 −5 M DNP; this concentration of DNP lowers the P O ratio only to a small extent, and induces only a slight ATPase activity. Serum albumin can partially protect against the uncoupling induced by DNP and other agents. Human skeletal muscle mitochondria show an ATPase activity which is stimulated by low concentrations and inhibited by high concentrations of Mg 2+. 10 −4 M DNP induces a high ATPase activity, which is inhibited by high Mg 2+ concentrations. The respiratory control ratio of human skeletal muscle mitochondria with pyruvate (+malate) is about 5–6 in the presence, and 10 or more in the absence of added ATP. The respiratory control ratio obtained in the presence of ATP is inversely related to the level of the Mg 2+-stimulated ATPase activity, whereas no such relation is found in the absence of added ATP. Also no relation is found between the level of Mg 2+-stimulated ATPase activity and the P O ratio with pyruvate (+ malate) or succinate. The hypothesis is advanced that the Mg 2+-stimulated ATPase of fresh skeletal muscle mitochondria is different in mechanism from the Mg 2+-stimulated ATPase found in aged liver mitochondria. The results are discussed in regard to the mechanism of mitochondrial respiratory control and its relation to oxidative phosphorylation and ATPase activities.

Influence d'injections de thyroxine sur la décarboxylation de l'acide l-glutamique par le cerveau du rat et sur celle de l'acide l-cystéinesulfinique par le foie du rat

Pyridoxal 5́-phosphate (PLP) is an important cofactor for amino acid decarboxylases with many biological functions, including the synthesis of signalling molecules, such as serotonin, dopamine, histamine, γ-aminobutyric acid, and taurine. Taurine is an abundant amino acid with multiple physiological functions, including osmoregulation, pH regulation, antioxidative protection, and neuromodulation. In mammalian tissues, taurine is mainly produced by decarboxylation of cysteine sulphinic acid to hypotaurine, catalysed by the PLP-dependent cysteine sulphinic acid decarboxylase (CSAD), followed by oxidation of the product to taurine. We determined the crystal structure of mouse CSAD and compared it to other PLP-dependent decarboxylases in order to identify determinants of substrate specificity and catalytic activity. Recognition of the substrate involves distinct side chains forming the substrate-binding cavity. In addition, the backbone conformation of a buried active-site loop appears to be a critical determinant for substrate side chain binding in PLP-dependent decarboxylases. Phe94 was predicted to affect substrate specificity, and its mutation to serine altered both the catalytic properties of CSAD and its stability. Using small-angle X-ray scattering, we further showed that CSAD presents open/close motions in solution. The structure of apo-CSAD indicates that the active site gets more ordered upon internal aldimine formation. Taken together, the results highlight details of substrate recognition in PLP-dependent decarboxylases and provide starting points for structure-based inhibitor design with the aim of affecting the biosynthesis of taurine and other abundant amino acid metabolites.

Some vitamin and amino acid interrelationships in Escherichia coli 113-3. I. The inhibitory effects of cystine and cysteinesulphinic acid.

Cystine, cysteinesulphinic acid (CSA), and other closely related sulphur-containing amino acids inhibited growth of Escherichia coli 113-3, particularly in aerobic conditions. The cystine inhibition was completely prevented by aspartic acid, partially reversed by pantothenic acid or β-alanine and slightly reversed by lysine or thiamine. The inhibitory effect of CSA was completely or partially reversed by aspartic acid, lysine, glutamic acid, proline, ornithine, or homoserine. Aspartic acid and glutamic acid appeared to reverse the inhibition competitively while lysine seemed to reverse the inhibition in a noncompetitive manner. Reversal of the inhibitory effect of relatively high concentrations of CSA by lysine was not complete, however, unless methionine was also present. Possible mechanisms of the cystine and CSA inhibition are discussed.

Formation de sulfite, d'acide cystéique et de taurine à partir de sulfate par l'oeuf embryonné

The formation of taurine, starting from the sulphate of the embryonic egg, is studied with the aid of 35S sulphate. The following reactions occur: (1) reduction of sulphate to sulphite; (2) fixation of the sulphite on a tricarbon chain with an amino group, resulting from the desulphydration of cysteine, which leads to the formation of l-cysteic acid; (3) decarboxylation of the l-cysteic acid. Reaction (1) takes place solely in the vitelline chamber cells; reaction (2) in the yolk; reaction (3) in the embryo as well as in the yolk. The decarboxylase actine on the l-cysteic acid is a specific enzyme, the action of which is inhibited by cysteine-sulphinic acid.

Isolation of 2-Aminoethanesulphinic Acid from a Mollusc

PAPER chromatographic analyses of extracts from Septifer (Mytilisepta) virgatus (Wiegmann) by means of the iodine–azide reaction1 showed the presence of an unusual sulphur compound, leading to its isolation. The isolate was identified as 2-aminoethanesulphinic acid. In 1951 Bergeret and Chatagner2 observed paper chromatographically that this compound was formed from cysteinesulphinic acid by the action of liver acetone powder. Furthermore, in 1953, Awapara and Wingo3 isolated 35S-2-aminoethanesulphinic acid and 35S-taurine from rat liver after injection of 35S-cysteine. 2-Aminoethanesulphinic acid, however, has never been reported to be isolated directly from organisms under natural conditions without administration of the precursors such as cysteinesulphinic acid, cysteine or cystine. We have found that every tissue of this Septifer contains this compound in considerable quantity.

La formation enzymatique de l'acide cystéinesulfinique á partir de sulfite par l'embryon de veau

Incubation of ground embryonic calf liver under nitrogen at 38°C with 35S-labelled sodium sulphite, pyruvate and glutamic acid, leads to the formation of 35S-cysteinesulphinic acid, isolated as the DNP-derivative. 35S-hypotaurine is also found, but not 35S-taurine or 35S-cystine. The amount of cysteinesulphinic acid present in the medium at the end of the incubation has been measured. In the presence of serine this amount is noticeably less. In the course of the incubation of the sulphine with embryonic calf liver, organic sulphur compounds without amino groups are also formed. Of these, one or more can be transformed, either directly or indirectly, into a product whose properties on paper ionophoresis are the same as those of cysteinesulphinic acid. Finally it has been established that under the conditions employed, cysteinesulphinic acid is not reduced to cystine. In vivo, on the contrary, this reduction is possible 2.

Pathways of Cysteine Synthesis in Aspergillus nidulans

SUMMARY: Cysteine was formed from sulphate, sulphite and thiosulphate as inorganic sulphur sources, by acetone-dried powders of Aspergillus nidulans mycelium. Added pyridoxal was obligatory for cysteine synthesis with sulphate or sulphite, and this synthesis was further enhanced by the addition of sodium pyruvate and sodium glutamate. Concomitant accumulation of cysteine sulphinic acid and utilization of glutamic acid was demonstrated. With thiosulphate, considerable synthesis of cysteine occurred in the absence of supplements, but was much enhanced by the addition of serine. Cysteine sulphinic acid did not accumulate with thiosulphate as the inorganic sulphur source. Parathiotrophic mutants, produced by ultraviolet irradiation, were used in the further elucidation of the biosynthetic mechanisms involved. Two reaction sequences: sulphate →sulphite →cysteine sulphinic acid →cysteine; and thiosulphate →cysteine-S-sulphonic acid →cysteine probably take place in the mould.

The mechanism of the inhibition of decarboxylases by ISOnicotinyl hydrazide

1. 1. The kinetics of inhibition of liver cysteine sulphinic acid decarboxylase by isonicotinyl hydrazide and hydroxylamine have been compared. 2. 2. Evidence is presented to suggest that decarboxylase inhibition is the result of interaction between the formyl group of pyridoxal phosphate and the inhibitor. 3. 3. It is suggested that the rate of inhibition of enzymes by isonicotinyl hydrazide may be used to demonstrate the presence of pyridoxal phosphate as a prosthetic group.

Amino acid decarboxylases in rat brain and liver

1. 1. Liver cysteine sulphinic acid decarboxylase is found in the clear supernatant of a liver suspension after fractional centrifugation, while brain cysteine sulphinic acid decarboxylase is more or less associated with particulate matter. 2. 2. Thiol groups and pyridoxal phosphate are shown to be necessary for the activity of liver and brain decarboxylases. 3. 3. Further evidence is presented to suggest that cysteine sulphinic and cysteic acids are decarboxylated by the same enzyme in the liver. 4. 4. Evidence is also given that glutamic, cysteine sulphinic and cysteic acids are decarboxylated by the same enzyme in the brain.