- Rationally engineered variants of S-adenosylmethionine (SAM) synthase: Reduced product inhibition and synthesis of artificial cofactor homologues
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S-Adenosylmethionine (SAM) synthase was engineered for biocatalytic production of SAM and long-chain analogues by rational re-design. Substitution of two conserved isoleucine residues extended the substrate spectrum of the enzyme to artificial S-alkylhomocysteines. The variants proved to be beneficial in preparative synthesis of SAM (and analogues) due to a much reduced product inhibition. This journal is
- Dippe,Brandt,Rost,Porzel,Schmidt,Wessjohann
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supporting information
p. 3637 - 3640
(2015/03/30)
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- Palatability of aquaculture feed
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A method for enhancing the palatability of aquaculture food, the method comprising treating the food with a compound of Formula I: wherein R1, R2, R3, and n are as defined herein, are disclosed.
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- Deamination and γ-Addition Reactions of Vinylglycine Catalyzed by Yeast Kynurenine Aminotransferase, and Suicidal Inactivation of the Enzyme during Its Processing
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Kynurenine aminotransferase from a yeast, Hansenula schneggii, has been found to catalyze the deamination of an olefinic amino acid, L-vinylglycine, to form α-ketobutyrate and ammonia.The maximum rate of deamination was 0.17 μmol/mg/min at 25 deg C (pH 8.0), which is approximately 1percent of the rate of transamination between L-kynurenine and α-ketoglutarate.Concomitantly with the catalysis, the enzyme lost both the deaminase and aminotransferase activities in a time-dependent manner.The inactivation was irreversible and followed pseudo-first-order kinetics at various concentrations of L-vinylglycine.The Michaelis constant for L-vinylglycine in the inactivation reaction was essentially the same as that in the deamination.These results indicate that the two reactions proceed through a common intermediary complex, and L-vinylglycine acts as a suicide inactivator for the enzyme.The apoenzyme neither catalyzed the deamination nor was inactivated by L-vinylglycine.The enzyme also catalyzes the γ-addition reaction of L-vinylglycine in the presence of alkanethiols producing the corresponding S-substituted homocysteines.
- Asada, Yasuhiko,Tanizawa, Katsuyuki,Yonaha, Kazuo,Soda, Kenji
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p. 2873 - 2878
(2007/10/02)
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- Sulfur containing trialkoxybenzoylamino carboxylic acids
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Compounds are prepared of the formula: STR1 wherein A is a straight or branched chain alkylene or alkylidene radical having 2 to 5 carbon atoms and which is substituted by an alkylthio group having 1 to 4 carbon atoms, a carboxymethyl thio group, a carboxyethyl thio group, an alkylsulfonyl group having 1 to 4 carbon atoms, a mercapto group, or the substituent on A together with --COR4 forms a 4 to 7 membered thiolactone ring, or A is substituted by an acylmercapto group wherein the acyl is benzoyl, a benzoyl radical substituted with one, two or three alkoxy groups with 1 to 6 carbon atoms, an alkanoyl radical of 1 to 6 carbon atoms, an alkenoyl radical of 3 to 6 carbon atoms, R1, R2 and R3 are the same or different and are alkyl groups of 1 to 5 carbon atoms and one of R1, R2 and R3 also can be hydrogen or the acyl radical of an alkanoic acid of 2 to 4 carbon atoms and R4 is a hydroxy group or an alkoxy group with 1 to 5 carbon atoms and their pharmacologically acceptable salts. The compounds are pharmacodynamically active and are suited for prophylaxis and treatment of heart illnesses such as cardiac ischemia, cardiac infarct, heart rhythm and circulatory disturbances.
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