Reactions catalysed by cysteine lyase from the yolk sac of chicken embryo

Tolosa, E.A.; Chepurnova, N.K.; Khomutov, R. M.; Severin, E. S.

doi:10.1016/0005-2744(69)90174-0

Cited by 24 publications

(4 citation statements)

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“…Cyanoalanine synthase catalyzes slow isotopic a-H exchange in cysteine and in end-product amino acids; the rates of a-H exchange in nonreacted (excess) cysteine are markedly increased in the presence of an adequate cosubstrate; no exchange is observed of H atoms in f3-position. In recent years we made comparative studies of some vitamin-B6-dependent lyases exclusively catalyzing replacement reactions of l-substituent in cysteine, serine, and related analogs (8,9,18,19,25). As a rule, these lyases, e.g., cysteine lyase (EC 4.4.1.10), serine sulfhydrase, and the identical or closely similar cystathionine j3-synthase (EC 4.2.1.22), use aliphatic thiols as cosubstrates (replacing agents).…”

mentioning

confidence: 99%

Beta-cyanoalanine synthase: purification and characterization.

Akopyan¹,

Braunstein²,

Goryachenkova³

1975

Proc. Natl. Acad. Sci. U.S.A.

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Beta-cyano-L~alanine synthase iL-cysteine hydrogen-sulfide-lyase (adding HCN), EC 4.4.1.91 was purified about 4000-fold from blue lupine seedlings. The enzyme was homogeneous on gel electrophoresis and free of contamination by other pyridoxal-P-dependent lyases. The enzyme has a molecular weight of 52,000 and contains 1 mole of pyridoxal-P per mole of protein; its isoelectric point is situated at pH 4.7. Its absorption spectrum has two maxima, at 280 and 410 nm. L-Cysteine is the natural primary (amino acid) substrate; jB-chloro-and ,3-thiocyano-L-alanine can substitute for it. Some small aliphatic thiols can serve (with considerably lower affinity) instead of cyanide as cosubstrates for cyanoalanine synthase. The synthase is refractory to DL-cycloserine and D-penicillamine, potent inhibitors of many pyridoxal-P-dependent enzymes. Cyanoalanine synthase catalyzes slow isotopic a-H exchange in cysteine and in end-product amino acids; the rates of a-H exchange in nonreacted (excess) cysteine are markedly increased in the presence of an adequate cosubstrate; no exchange is observed of H atoms in f3-position. In recent years we made comparative studies of some vitamin-B6-dependent lyases exclusively catalyzing replacement reactions of l-substituent in cysteine, serine, and related analogs (8,9,18,19,25). As a rule, these lyases, e.g., cysteine lyase (EC 4.4.1.10), serine sulfhydrase, and the identical or closely similar cystathionine j3-synthase (EC 4.2.1.22), use aliphatic thiols as cosubstrates (replacing agents). It seemed of particular interest to extend our studies to (CN)Ala synthase, a jB-lyase utilizing cyanide as the preferred cosubstrate.Abbreviations: Pyridoxal-P, pyridoxal-5'-phosphate; (CN)Ala, fl-cyano-L-alanine; (Cl)Ala, B-chloroalanine; (CNS)Ala, fl-thiocyano-i>alanine; HS-EtOH, 2-mercaptoethanol; r.s.r., relative specific radioactivity. 1617 In this paper, we present an improved purification procedure for (CN)Ala synthase, and report on some general and catalytic properties of the enzyme. MATERIALS AND METHODSReagents and Instruments. All chemicals were preparations of highest purity available, namely: DEAE-Sephadex A-50 and Sephadex G-100 (Pharmacia, Uppsala); hydroxylapatite from Bio-Rad; pyridoxal-P (Reanal, Budapest); dansyl chloride (Merck); reference dansylamino acids (from "Serva"); 3H20 (61 mCi/ml), made in USSR. Aluminum hydroxide C.) was prepared according to Willstatter and Kraut (27). We thank Dr. Drell (Calbiochem) for the gift of a sample of ,B-cyanoalanine.Reagents and apparatus for analytical gel electrophoresis were supplied by Reanal; Ampholine buffers and equipment for isoelectrofocusing, by LKB Producter (Stockholm).Chromatographic and electrophoretic separations were performed on papers FN-4 and FN-16 ("Filtrak", German Democratic Republic). All buffer solutions used were Tris HC1 of pH 8.8, in the concentrations indicated.Enzyme Activity Assays. (CN)Ala synthase activity assays were based on the rates of formation of end-products-H2S, (CN

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confidence: 99%

Beta-cyanoalanine synthase: purification and characterization.

Akopyan¹,

Braunstein²,

Goryachenkova³

1975

Proc. Natl. Acad. Sci. U.S.A.

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“…Since the repression of synthesis of this enzyme was very sensitive to both methionine and adenosylmethionine (Table 1), insensitivity of the synthesized enzyme to the end product(s) in the reaction would be negligible for the cell to regulate the metabolism at this step. Serine sulfhydrylases of S. cerevisiae (29), Aspergillus nidulans (25), and animal liver (3,32) have been reported to catalyze CTT ␤-synthesis as well. Therefore, the possibility that OAS sulfhydrylase synthesized in T. thermophilus cells cultured with methionine as a sole sulfur source (Table 1) catalyzed a CTT ␤-synthase reaction to make reversed transsulfuration functional was examined.…”

Section: Discussionmentioning

confidence: 99%

Occurrence of Transsulfuration in Synthesis of l -Homocysteine in an Extremely Thermophilic Bacterium, Thermus thermophilus HB8

Yamagata¹,

Ichioka²,

Goto³

et al. 2001

J Bacteriol

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Transsulfuration is the main reaction in microorganisms (30) and plants (11) to incorporate sulfur into a four-carbon amino acid, L-homocysteine, which is produced from L-cystathionine (CTT) through a reaction catalyzed by cystathionine ␤-lyase (EC 4.4.1.8). These organisms first synthesize L-cysteine with O-acetyl-L-serine (OAS) and sulfide and subsequently synthesize CTT with L-cysteine and L-homoserine by the catalysis of CTT ␥-synthase (EC 4.2.99.9). This enzyme reacts with an activated form of L-homoserine: O-acetyl-Lhomoserine (OAH) (fungi and some bacteria) (4,15,24), O-succinyl-L-homoserine (enteric and some other bacteria) (11, 13, 28), or O-phosphoryl-L-homoserine (plants) (9,26). Thus, many organisms obtain homocysteine by incorporating sulfur that is first assimilated into cysteine, via CTT. However, a few microorganisms synthesize homocysteine directly through a replacement reaction of OAH with sulfide that is catalyzed by OAH sulfhydrylase (EC 4.2.99.10) (6,23,34).Little is known about sulfur metabolism and the related enzymes of bacteria living under extreme conditions such as alkaline pH or high temperature. Some archaea have been reported to synthesize cysteine from methionine through reversed transsulfuration from homocysteine to cysteine (36), but an OAS sulfhydrylase (EC 4.2.99.8) has been purified from an archaeon and characterized in detail, suggesting that the enzyme is functional as a cysteine synthase (1). Thus, two groups of archaea can be distinguished with respect to cysteine synthesis. This is supported by the result of genome analysis (16) showing that some archaea have genes homologous to the OAS sulfhydrylase gene of enteric bacteria, while others do not. Recently, we have found that an alkaliphilic bacterium produces a very large amount of OAS sulfhydrylase, the specific activity of which is very low compared with that of other microorganisms (31). Its extreme stability to heat and alkaline pHs is also notable. We have recently found activities of CTT ␥-synthase, CTT ␤-lyase, and OAH sulfhydrylase in a cell extract of an extremely thermophilic bacterium, Thermus thermophilus HB8, in addition to a very high OAS sulfhydrylase activity (35). On the other hand, Kosuge et al. (17,18) have reported that T. thermophilus HB27 synthesizes homocysteine through direct sulfhydrylation of OAH and that transsulfuration is not func-* Corresponding author. Mailing address:

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“…This product could then be converted into cysteic acid by undergoing a dephosphorylation and oxidation followed by a transamination of the resulting 3-sulfopyruvate. It is clear that the acceptor could not be cysteine, which is known to be converted into cysteic acid by cysteine lyase (33), or an a-aminoacrylic acid compound generated either from cysteine, seine, or a product derived directly from these, i.e., 0-acetylserine.…”

Section: Methodsmentioning

confidence: 99%

Biosynthesis of the sulfonolipid 2-amino-3-hydroxy-15-methylhexadecane-1-sulfonic acid in the gliding bacterium Cytophaga johnsonae

White¹

1984

J Bacteriol

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The biosynthesis of the sulfonolipid 2-amino-3-hydroxy-15-methylhexadecane-1-sulfonic acid (capnine) was studied by measuring the incorporation of possible precursors into the lipid by cells grown in the presence of ?recursors which were labeled with stable isotopes. Cells grown on yeast extract in the presence of DL-[3,3-H2dserine contained 40.1 mol% of the protein-bound serine and 5.0 mol% of the protein-bound cysteine derived from the labeled s,rine. Cells grown in the presence of DL-[3,3-2H21cystine contained labeled L-cysteine in which 48.4 mol% of the protein-bound cysteine was derived from the exogenous cystine. In both cases, no label was found in the capnine. Cells grown in the presence of L-[sulfonwc-1803Jcysteic acid, however, incorporated the cysteic acid into the sulfonolipid with little or no isotopic dilution. Capnine isolated from cells grown in the presence of DL-[3,3-2_H2cysteic acid contained 86.4 mol% of the molecules that had two deuteriums. These results are consistent with the possiblity, that biosynthesis of capnine occurs by the condensation of 13-methylmyristoyl-coenzyme A with cysteic acid, in a reaction analogous to the condensation of a palmitoyl-coenzyme A with serine to form 3-keto-sphinganine during the biosynthesis of sphingolipids.

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Reactions catalysed by cysteine lyase from the yolk sac of chicken embryo

Cited by 24 publications

References 2 publications

Beta-cyanoalanine synthase: purification and characterization.

Beta-cyanoalanine synthase: purification and characterization.

Occurrence of Transsulfuration in Synthesis of l -Homocysteine in an Extremely Thermophilic Bacterium, Thermus thermophilus HB8

Biosynthesis of the sulfonolipid 2-amino-3-hydroxy-15-methylhexadecane-1-sulfonic acid in the gliding bacterium Cytophaga johnsonae

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