- NEW METHIONINE METABOLIC PATHWAY INHIBITORS
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Novel compounds capable of inhibiting methionine metabolic pathway are provided. These compounds are used in inhibiting cystathionin γ-synthase (CGS) in general, and in plants, fungi and bacteria, in particular. These compounds of the invention are used as herbicides, pesticides, fungicides, agricultural plant stimulants or antimicrobial agents. The compounds of the present invention can be used for seed treatment. In particular, the compounds of the invention are used as selective herbicides, non-selective herbicides, agricultural herbicides, non-agricultural herbicides or weed killers, herbicides in integrated pest management, herbicides in gardening, herbicides in clearing waste ground, herbicides in clearing industrial or constructions sites, or herbicides in clearing railways and railway embankments.
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Paragraph 0113
(2019/08/08)
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- Biogenesis of Hydrogen Sulfide and Thioethers by Cystathionine Beta-Synthase
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Aims: The transsulfuration pathway enzymes cystathionine beta-synthase (CBS) and cystathionine gamma-lyase are thought to be the major source of hydrogen sulfide (H2S). In this study, we assessed the role of CBS in H2S biogenesis. Results: We show that despite discouraging enzyme kinetics of alternative H2S-producing reactions utilizing cysteine compared with the canonical condensation of serine and homocysteine, our simulations of substrate competitions at biologically relevant conditions suggest that cysteine is able to partially compete with serine on CBS, thus leading to generation of appreciable amounts of H2S. The leading H2S-producing reaction is condensation of cysteine with homocysteine, while cysteine desulfuration plays a dominant role when cysteine is more abundant than serine and homocysteine is limited. We found that the serine-to-cysteine ratio is the main determinant of CBS H2S productivity. Abundance of cysteine over serine, for example, in plasma, allowed for up to 43% of CBS activity being responsible for H2S production, while excess of serine typical for intracellular levels effectively limited such activity to less than 1.5%. CBS also produced lanthionine from serine and cysteine and a third of lanthionine coming from condensation of two cysteines contributed to the H2S pool. Innovation: Our study characterizes the H2S-producing potential of CBS under biologically relevant conditions and highlights the serine-to-cysteine ratio as the main determinant of H2S production by CBS in vivo. Conclusion: Our data clarify the function of CBS in H2S biogenesis and the role of thioethers as surrogate H2S markers.
- Majtan, Tomas,Krijt, Jakub,Sokolová, Jitka,K?í?ková, Michaela,Ralat, Maria A.,Kent, Jana,Gregory, Jesse F.,Ko?ich, Viktor,Kraus, Jan P.
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p. 311 - 323
(2018/01/05)
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- Influence of Sulfur-Containing Diamino Acid Structure on Covalently Crosslinked Copolypeptide Hydrogels
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Biologically occurring non-canonical di-α-amino acids were converted into new di-N-carboxyanhydride (di-NCA) monomers in reasonable yields with high purity. Five different di-NCAs were separately copolymerized with tert-butyl-l-glutamate NCA to obtain covalently crosslinked copolypeptides capable of forming hydrogels with varying crosslinker density. Comparison of hydrogel properties with residue structure revealed that different di-α-amino acids were not equivalent in crosslink formation. Notably, l-cystine was found to produce significantly weaker hydrogels compared to l-homocystine, l-cystathionine, and l-lanthionine, suggesting that l-cystine may be a sub-optimal choice of di-α-amino acid for preparation of copolypeptide networks. The di-α-amino acid crosslinkers also provided different chemical stability, where disulfide crosslinks were readily degraded by reduction, and thioether crosslinks were stable against reduction. This difference in response may provide a means to fine tune the reduction sensitivity of polypeptide biomaterial networks.
- Raftery, Eric D.,Gharkhanian, Eric G.,Ricapito, Nicole G.,McNamara,Deming, Timothy J.
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p. 3547 - 3553
(2018/09/25)
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- Synthesis and evaluation of L-cystathionine as a standard for amino acid analysis
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L-Cystathionine is a key nonprotein amino acid related to metabolic conditions. The quantitative determination of L-cystathionine in physiological fluids by amino acid analysis is important for clinical diagnosis; however, certified reference material for L-cystathionine with satisfactory purity, content, and quantity has been unavailable until recently. Consequently, a practical and simple method for the preparation of L-cystathionine was examined, which involves thioalkylation of N-tert-butoxycarbonyl-Lcysteine tert-butyl ester, derived from L-cystine, with (2S)-2-(tert-butoxycarbonyl)amino-4-iodobutanoic acid tert-butyl ester, derived from L-aspartic acid, to obtain L-cystathionine with protecting groups, followed by single-step deprotection under mild conditions. This method produces L-cystathionine in high purity (99.4%) and having sufficient percentage content according to amino acid analysis, which could be used as a standard for the amino acid analysis of physiological fluids.
- Amino, Yusuke,Suzuki, Yumiko
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- Detection of reaction intermediates during human cystathionine β-synthase-monitored turnover and H2S production
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Human cystathionine β-synthase (CBS), a novel heme-containing pyridoxal 5′-phosphate enzyme, catalyzes the condensation of homocysteine and serine or cysteine to produce cystathionine and H2O or H 2S, respectively. The presence of he
- Yadav, Pramod Kumar,Banerjee, Ruma
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p. 43464 - 43471
(2013/03/13)
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- Residue N84 of Yeast Cystathionine β-Synthase is a Determinant of Reaction Specificity
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Cystathionine β-synthase (CBS) catalyzes the pyridoxal 5'-phosphate (PLP)-dependent condensation of l-serine and l-homocysteine to form l-cystathionine in the first step of the reverse transsulfuration pathway. Residue N84 of yeast CBS (yCBS), predicted to form a hydrogen bond with the hydroxyl moiety of the PLP cofactor, was mutated to alanine, aspartate and histidine. The truncated form of yCBS (ytCBS, residues 1-353) was employed in this study to eliminate any effects of the C-terminal, regulatory domain. The kcat/Kml-Ser of the N84A, N84D and N84H mutants for the β-replacement reaction is reduced by a factor of 230, 11000 and 640, respectively. Fluorescence resonance energy transfer between tryptophan residue(s) of the enzyme and the PLP cofactor, observed in the wild-type enzyme and N84A mutant, is altered in N84H and absent in N84D. PLP saturation values of 73%, 30% and 67% were observed for the alanine, aspartate and histidine mutants, respectively, compared to 98% for the wild-type enzyme. A marginal β-elimination activity was detected for N84D (kcat/Kml-Ser = 0.23 ± 0.02 M-1 s-1) and N84H (kcat/Kml-Ser = 0.34 ± 0.06 M-1 s-1), in contrast with wild-type ytCBS and the N84A mutant, which do not catalyze this reaction. The ytCBS-N84D enzyme is also inactivated upon incubation with l-serine, via an aminoacrylate-mediated mechanism. These results demonstrate that residue N84 is essential in maintaining the orientation of the pyridine ring of the PLP cofactor and the equilibrium between the open and closed conformations of the active site.
- Lodha, Pratik H.,Hopwood, Emily M.S.,Manders, Adrienne L.,Aitken, Susan M.
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experimental part
p. 1424 - 1431
(2011/11/13)
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- Synthesis of optically active homocysteine from methionine and its use in preparing four stereoisomers of cystathionine
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In order to synthesize four stereoisomers of cystathionine (CYT), D- and L-homocysteines (D- and L-Hcy) were synthesized from methionine (Met) by a facile procedure. L-Met was reacted with dichloroacetic acid in concentrated hydrochloric acid under reflux to give (4S)-1,3-thiazane-2,4-dicarboxylic acid hydrochloride [(4S)-TDC? HCl]. L-Hcy was obtained by treatment of (4S)-TDC? HCl with hydroxylamine. D-Hcy was also synthesized from D-Met via (4R)-TDC? HCl intermediate. The obtained D- and L-Hcy were condensed with (R)- and (S)-2-amino-3-chloropropanoic acid hydrochlorides under alkaline conditions to give four stereoisomers of CYT.
- Shiraiwa, Tadashi,Nakagawa, Kazuo,Kanemoto, Norito,Kinda, Tomohiro,Yamamoto, Hiroki
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p. 1081 - 1085
(2007/10/03)
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- L-CYSTATHIONINE DERIVATIVES FOR THE SYNTHESIS OF PEPTIDES
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The preparation is described of L-cystathionine derivatives with amino protecting groups, which can readily be cleaved acidolytically and permit a selective acylation of both amino groups, and of a derivative with carboxyls protected by different groups.
- Prochazka, Zdenko,Jost, Karel
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p. 1982 - 1990
(2007/10/02)
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