816-66-0Relevant articles and documents
Corbett,Fooks
, p. 1909 (1967)
Structural and functional evolution of isopropylmalate dehydrogenases in the leucine and glucosinolate pathways of Arabidopsis thaliana
He, Yan,Galant, Ashley,Pang, Qiuying,Strul, Johanna M.,Balogun, Sherifat F.,Jez, Joseph M.,Chen, Sixue
, p. 28794 - 28801 (2011)
The methionine chain-elongation pathway is required for aliphatic glucosinolate biosynthesis in plants and evolved from leucine biosynthesis. In Arabidopsis thaliana, three 3-isopropylmalate dehydrogenases (AtIPMDHs) play key roles in methionine chain-elongation for the synthesis of aliphatic glucosinolates (e.g. AtIPMDH1) and leucine (e.g. AtIPMDH2 and AtIPMDH3). Here we elucidate the molecular basis underlying the metabolic specialization of these enzymes. The 2.25 A° resolution crystal structure of AtIPMDH2 was solved to provide the first detailed molecular architecture of a plant IPMDH. Modeling of 3-isopropylmalate binding in the AtIPMDH2 active site and sequence comparisons of prokaryotic and eukaryotic IPMDH suggest that substitution of one active site residue may lead to altered substrate specificity and metabolic function. Sitedirected mutagenesis of Phe-137 to a leucine in AtIPMDH1 (AtIPMDH1-F137L) reduced activity toward 3-(2′-methylthio)-ethylmalate by 200-fold, but enhanced catalytic efficiency with 3-isopropylmalate to levels observed with AtIPMDH2 and AtIPMDH3. Conversely, the AtIPMDH2-L134F and AtIPMDH3-L133F mutants enhanced catalytic efficiency with 3-(2′-methylthio)ethylmalate ～100-fold and reduced activity for 3-isopropylmalate. Furthermore, the altered in vivo glucosinolate profile of an Arabidopsis ipmdh1 T-DNA knock-out mutant could be restored to wild-type levels by constructs expressing AtIPMDH1, AtIPMDH2-L134F, or AtIPMDH3-L133F, but not by AtIPMDH1-F137L. These results indicate that a single amino acid substitution results in functional divergence of IPMDH in planta to affect substrate specificity and contributes to the evolution of specialized glucosinolate biosynthesis from the ancestral leucine pathway.
Coenzyme activity of NAD analogs for 3-isopropylmalate dehydrogenase from Thermus thermophilus HB8
Chiba, Akira,Eguchi, Tadashi,Oshima, Tairo,Kakinuma, Katsumi
, p. 1647 - 1649 (1999)
In order to elucidate the enzyme-substrate-cofactor interaction in 3-isopropylmalate dehydrogenase, the coenzyme activity of NAD analogs which have a 3-substituted pyridine ring was examined. Analogs 3-5 showed diminished kcat values compared with those of NAD+, whereas thiocarboxamide 2 was almost as equally active as NAD+. This suggests that the NH2 functionality of NAD+ is more important for the catalysis of IPMDH than a carbonyl group.
Palladium-Catalyzed β-Arylation of α-Keto Esters
Zavesky, Blane P.,Bartlett, Samuel L.,Johnson, Jeffrey S.
, p. 2126 - 2129 (2017)
A catalyst system derived from commercially available Pd2(dba)3 and PtBu3 has been applied to the coupling of α-keto ester enolates and aryl bromides. The reaction provides access to an array of β-stereogenic α-keto esters. When the air-stable ligand precursor PtBu3·HBF4 is employed, the reaction can be carried out without use of a glovebox. The derived products are of broad interest given the prevalence of the α-keto acid substructure in biologically important molecules.
Chemoenzymatic Production of Enantiocomplementary 2-Substituted 3-Hydroxycarboxylic Acids from l-α-Amino Acids
Pickl, Mathias,Marín-Valls, Roser,Joglar, Jesús,Bujons, Jordi,Clapés, Pere
, p. 2866 - 2876 (2021/04/14)
A two-enzyme cascade reaction plus in situ oxidative decarboxylation for the transformation of readily available canonical and non-canonical l-α-amino acids into 2-substituted 3-hydroxycarboxylic acid derivatives is described. The biocatalytic cascade consisted of an oxidative deamination of l-α-amino acids by an l-α-amino acid deaminase from Cosenzaea myxofaciens, rendering 2-oxoacid intermediates, with an ensuing aldol addition reaction to formaldehyde, catalyzed by metal-dependent (R)- or (S)-selective carboligases namely 2-oxo-3-deoxy-l-rhamnonate aldolase (YfaU) and ketopantoate hydroxymethyltransferase (KPHMT), respectively, furnishing 3-substituted 4-hydroxy-2-oxoacids. The overall substrate conversion was optimized by balancing biocatalyst loading and amino acid and formaldehyde concentrations, yielding 36–98% aldol adduct formation and 91–98% ee for each enantiomer. Subsequent in situ follow-up chemistry via hydrogen peroxide-driven oxidative decarboxylation afforded the corresponding 2-substituted 3-hydroxycarboxylic acid derivatives. (Figure presented.).
Exploration of Transaminase Diversity for the Oxidative Conversion of Natural Amino Acids into 2-Ketoacids and High-Value Chemicals
Chen, Yanchun,Cui, Xuexian,Cui, Yinglu,Li, Chuijian,Li, Ruifeng,Li, Tao,Sun, Jinyuan,Wu, Bian,Zhu, Tong
, p. 7950 - 7957 (2020/08/21)
The use of 2-ketoacids is very common in feeds, food additives, and pharmaceuticals, and 2-ketoacids are valuable precursors for a plethora of chemically diverse compounds. Biocatalytic synthesis of 2-ketoacids starting from l-amino acids would be highly desirable because the substrates are readily available from biomass feedstock. Here, we report bioinformatic exploration of a series of aminotransferases (ATs) to achieve the desired conversion. Thermodynamic control was achieved by coupling an l-glutamate oxidation reaction in the cascade for the recycling of the amine acceptor. These enzymes were able to convert a majority of proteinogenic amino acids into the corresponding 2-ketoacids with high conversion (up to 99percent) and atom-efficiency. Furthermore, this enzyme cascade was extendable, and one-pot two-step processes were established for the synthesis of d-amino acids and N-methylated amino acids, achieving great overall conversion (up to 99percent) and high ee values (>99percent). These developed enzymatic methodologies offer convenient routes for utilizing amino acids as synthetic reagents.
