Deamination and γ‐addition reactions of vinylglycine by L‐methionine γ‐lyase

Esaki, Nobuyoshi; Suzuki, Tomohiko; Tanaka, Hidehiko; Soda, Kenji; Rando, Robert R.

doi:10.1016/0014-5793(77)80713-8

Cited by 30 publications

(11 citation statements)

References 18 publications

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“…This is also consistent with the idea that the C-S bond cleavage is a rate-determining step of the enzyme as reported by a 1 H-NMR study on MGL from Pseudomonas putida [44]. TFM > DFM > methionine) would suggest that the inductive effect and anionic hyperconjugation of the fluorinated methyl thiolates improve its leaving ability.…”

Section: Discussionsupporting

confidence: 91%

Mechanistic studies on the enzymatic processing of fluorinated methionine analogues by Trichomonas vaginalis methionine γ-lyase

Moya

Westrop

Coombs

et al. 2011

Biochemical Journal

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TFM (L-trifluoromethionine), a potential prodrug, was reported to be toxic towards human pathogens that express MGL (L-methionine γ-lyase; EC 4.4.1.11), a pyridoxal phosphate-containing enzyme that converts L-methionine into α-oxobutyrate, ammonia and methyl mercaptan. It has been hypothesized that the extremely reactive thiocarbonyl difluoride is produced when the enzyme acts upon TFM, resulting in cellular toxicity. The potential application of the fluorinated thiomethyl group in other areas of biochemistry and medicinal chemistry requires additional studies. Therefore a detailed investigation of the theoretical and experimental chemistry and biochemistry of these fluorinated groups (CF₃S⁻ and CF₂HS⁻) has been undertaken to trap and identify chemical intermediates produced by enzyme processing of molecules containing these fluorinated moieties. TvMGL (MGL from Trichomonas vaginalis) and a chemical model system of the reaction were utilized in order to investigate the cofactor-dependent activation of TFM and previously uninvestigated DFM (L-difluoromethionine). The differences in toxicity between TFM and DFM were evaluated against Escherichia coli expressing TvMGL1, as well as the intact human pathogen T. vaginalis. The relationship between the chemical structure of the reactive intermediates produced from the enzymatic processing of these analogues and their cellular toxicity are discussed.

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Section: Discussionsupporting

confidence: 91%

Mechanistic studies on the enzymatic processing of fluorinated methionine analogues by Trichomonas vaginalis methionine γ-lyase

Moya

Westrop

Coombs

et al. 2011

Biochemical Journal

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“…Cheese ripening flora such as Pseudomonas sp. (Esaki et al 1977), Penicillium sp (Ruiz-Herrera and Starkey 1969), Brevibacterium sp. (Ferchichi et al 1985) and Geotrichum sp (Arfi et al 2006) were reported as methanethiol producers.…”

Section: Introductionmentioning

confidence: 99%

Characterization and immobilization of purified Aspergillus flavipesl-methioninase: continuous production of methanethiol

Elsayed

Shindia

2011

Journal of Applied Microbiology

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Aims: To immobilize the purified Aspergillus flavipesl‐methioninase on solid carriers for continuous production of methanethiol with high purity, by the enzymatic methods. Methods and Results: The purified l‐methioninase was immobilized using different methods, and physicochemical and kinetic studies for the potent immobilized enzyme were conducted parallel to the soluble one. The activity of the purified extracellular enzyme was 1·8‐fold higher than intracellular one from submerged cultures of A. flavipes. Among the tested methods, polyacrylamide (42·2%), Ca‐alginate (40·9%) and chitin (40·8%) displayed the highest immobilization efficiency. The thermal inactivation rate was strongly decreased for chitin‐immobilized enzyme (0·222 s−1) comparing to soluble enzyme (0·51 s−1). Enzyme immobilization efficiency was greatly improved using 4·0% glutaraldehyde and 41·6/6·3 (T/C) as spacers for chitin and polyacrylamide‐enzyme conjugates, comparing to their controls. Also the incorporation of lysine, glutathione, cysteine and dithiothreitol as active site protectants significantly enhance the catalytic efficiency of immobilized enzyme. The activity of enzyme was increased by 4·5‐ and 3·5‐fold using glutathione plus DDT and glutathione plus methionine, for chitin and polyacrylamide enzyme, respectively. Conclusion: Chitin enzyme gave a plausible stability till fourth cycle for production of methanethiol under controlled system. Applying GC and HNMR analysis, methanethiol has identical chemical structure to the standard compound. Significance and Impact of the Study: Technically, a new method for continuous production of pure methanethiol, with broad applications, was developed using a simple low expenses method.

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“…from Pseudomonas spp. (Tanaka et al, 1976;Ito et al, 1976;Tanaka et al, , 1985Esaki et al, 1977;Nakayama et al, 1984b), Aeromonas sp. (Nakayama et al, 1984a) and Aspergillus sp.…”

Section: Introductionmentioning

confidence: 99%

Induction of Methanethiol Production by Brevibacterium linens CNRZ 918

1986

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A non-inducing medium (NID) was defined for studying the induction of methanethiol production by Brevibacterium linens CNRZ 9 18. The lowest L-methionine concentration capable of inducing maximal methanethiol production by the cells was 7 mM. The peptides L-Ala-L-Met and L-Met-L-Ala induced greater methanethiol production than free L-methionine. DMethionine, L-cysteine, S-methyl-L-cysteine and L-ethionine were poor inducers. Culture temperature affected the duration of induction. An Na+ concentration of 1 M in the culture medium led to maximal methanethiol production capacity of both cells and cell extracts. LMethionine and L-ethionine were the best substrates for the crude soluble cells extract (with release of methanethiol and ethanethiol respectively). Neither the derivatives of L-methionine that acted as inducers, nor D-methionine, were substrates for demethiolation. Demethiolation activity of the crude extract was thermolabile, not stimulated by Na+ and strongly inhibited by Zn2+, Mn2+ and Cu2+. The shortest generation time obtained for B. linens CNRZ 918 in NID medium + L-methionine was 4 h at 26 "C. Only coccoid forms were present when the culture temperature was 30 "C. The presence of L-methionine in the medium favoured their appearance.The strain grew best in the presence of 1 % NaCl but tolerated concentrations up to 15%. The induction of methfiethiol production was due to the inductionbf L-methionine-y-demethiolase. The level of induction was probably related to the intracellular concentration of L-methionine. The transport system of L-methionine by B. linens CNRZ918 was constitutive and Na+ dependent.

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Deamination and γ‐addition reactions of vinylglycine by L‐methionine γ‐lyase

Cited by 30 publications

References 18 publications

Mechanistic studies on the enzymatic processing of fluorinated methionine analogues by Trichomonas vaginalis methionine γ-lyase

Mechanistic studies on the enzymatic processing of fluorinated methionine analogues by Trichomonas vaginalis methionine γ-lyase

Characterization and immobilization of purified Aspergillus flavipesl-methioninase: continuous production of methanethiol

Induction of Methanethiol Production by Brevibacterium linens CNRZ 918

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