scholarly journals Reaction Mechanism of Prephenate Dehydrogenase from the Alternative Tyrosine Biosynthesis Pathway in Plants

ChemBioChem ◽  
2018 ◽  
Vol 19 (11) ◽  
pp. 1132-1136 ◽  
Author(s):  
Cynthia K. Holland ◽  
Joseph M. Jez
Keyword(s):  
Reaction Mechanism ◽  
Biosynthesis Pathway ◽  
Prephenate Dehydrogenase ◽  
Tyrosine Biosynthesis

scholarly journals Biosynthesis of resveratrol derivatives and evaluation of their anti-inflammatory activity

2021 ◽  
Vol 64 (1) ◽  
Author(s):  
Yoojin Chong ◽  
Hye Lim Lee ◽  
Jihyeon Song ◽  
Youngshim Lee ◽  
Bong-Gyu Kim ◽  
...  
Keyword(s):  
Biological Activities ◽  
Stilbene Synthase ◽  
Inflammatory Activity ◽  
E Coli ◽  
Prephenate Dehydrogenase ◽  
Coa Ligase ◽  
Final Yield ◽  
Resveratrol Derivatives ◽  
Anti Inflammatory ◽  
Tyrosine Biosynthesis

AbstractResveratrol is a typical plant phenolic compound whose derivatives are synthesized through hydroxylation, O-methylation, prenylation, and oligomerization. Resveratrol and its derivatives exhibit anti-neurodegenerative, anti-rheumatoid, and anti-inflammatory effects. Owing to the diverse biological activities of these compounds and their importance in human health, this study attempted to synthesize five resveratrol derivatives (isorhapontigenin, pterostilbene, 4-methoxyresveratrol, piceatannol, and rhapontigenin) using Escherichia coli. Two-culture system was used to improve the final yield of resveratrol derivatives. Resveratrol was synthesized in the first E. coli cell that harbored genes for resveratrol biosynthesis including TAL (tyrosine ammonia lyase), 4CL (4-coumaroyl CoA ligase), STS (stilbene synthase) and genes for tyrosine biosynthesis such as aroG (deoxyphosphoheptonate aldolase) and tyrA (prephenate dehydrogenase). Thereafter, culture filtrate from the first cell was used for the modification reaction carried out using the second E. coli harboring hydroxylase and/or O-methyltransferase. Approximately, 89.8 mg/L of resveratrol was synthesized and using the same, five derivatives were prepared with a conversion rate of 88.2% to 22.9%. Using these synthesized resveratrol derivatives, we evaluated their anti-inflammatory activity. 4-Methoxyresveratrol, pterostilbene and isorhapontigenin showed the anti-inflammatory effects without any toxicity. In addition, pterostilbene exhibited the enhanced anti-inflammatory effects for macrophages compared to resveratrol.

Phenylalanine and Tyrosine Biosynthesis in Sporeforming Members of the Order Actinomycetales

1987 ◽  
Vol 42 (4) ◽  
pp. 387-393 ◽  
Author(s):  
Hilda-K. Hund ◽  
Brigitte Keller ◽  
Franz Lingens
Keyword(s):  
Anion Exchange ◽  
Deae Cellulose ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Chorismate Mutase ◽  
Biosynthetic Enzymes ◽  
Prephenate Dehydratase ◽  
Prephenate Dehydrogenase ◽  
Arogenate Dehydrogenase ◽  
Tyrosine Biosynthesis

Abstract The enzymes of the terminal steps of phenylalanine and tyrosine biosynthesis, chorismate mutase, prephenate dehydratase, arogenate dehydratase, prephenate dehydrogenase and aroge­ nate dehydrogenase were studied in 13 sporeforming members of the order Actinomycetales. In these organisms tyrosine is synthesized exclusively via arogenate, phenylalanine, however, via phenylpyruvate. The regulation pattern of the corresponding enzymes was determined: No feed­ back inhibition of arogenate dehydrogenase by L-phenylalanine and ʟ-tyrosine was observed. Chorismate mutase was found to be inhibited in all organisms by ʟ-tyrosine and in most organisms by ʟ-tryptophan. ʟ-Phenylalanine was shown to inhibit prephenate dehydratase in the majority of bacteria tested and ʟ-tyrosine activated this enzyme in most cases. The elution profiles for the phenylalanine and tyrosine biosynthetic enzymes were studied in three members of the order Actinomycetales by anion exchange chromatography on DEAE-cellulose.

Purification and Properties of Arogenate Dehydrogenase from Actinoplanes missouriensis

1989 ◽  
Vol 44 (9-10) ◽  
pp. 797-801 ◽  
Author(s):  
Hilda-K. Hund ◽  
Gerda Bär ◽  
Franz Lingens
Keyword(s):  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Prephenate Dehydrogenase ◽  
Step Procedure ◽  
Purification And Properties ◽  
Arogenate Dehydrogenase ◽  
Tyrosine Biosynthesis ◽  
Specific Reagent

Abstract Actinoplanes missouriensis utilizes arogenate as an intermediate in ʟ-tyrosine biosynthesis, while no evidence of prephenate dehydrogenase was observed. Arogenate dehydrogenase has been partially purified by a five-step procedure. The enzyme requires NAD as cofactor. The Km values for NAD and arogenate are 0.2 mм and 0.15 mм, respectively. The molecular weight of arogenate dehydrogenase is about 68,000, and SDS gel electrophoresis indicates a composition of two identical subunits. The enzyme is not feedback inhibited by ʟ-tyrosine and unaffected by ʟ-phenylalanine, prephenate, phenylpyruvate, p-hydroxyphenylpyruvate or ʟ-tryptophan. Arogenate dehydrogenase is quite sensitive to p-hydroxymercuribenzoate with 50% inhibition at 12.5 μм of the SH -specific reagent. The presence of malate in usually applied arogenate preparations is demonstrated and the consequence of an impure substrate on arogenate dehydrogenase studies is discussed.

Tyrosine Biosynthesis in Sorghum bicolor: Isolation and Regulatory Properties of Arogenate Dehydrogenase

1986 ◽  
Vol 41 (1-2) ◽  
pp. 69-78 ◽  
Author(s):  
James A. Connelly ◽  
Eric E. Conn
Keyword(s):  
Amino Acid ◽  
Deae Cellulose ◽  
Shikimate Pathway ◽  
Oxidative Decarboxylation ◽  
Strong Inhibition ◽  
High Recovery ◽  
Prephenate Dehydrogenase ◽  
Arogenate Dehydrogenase ◽  
Tyrosine Biosynthesis ◽  
Regulatory Properties

Abstract The conversion of prephenic acid to tyrosine can occur by two different routes: (a) oxidative decarboxylation (prephenate dehydrogenase) followed by transamination (aromatic aminotrans­ ferase); (b) transamination of prephenate forming the non-aromatic amino acid arogenic acid (prephenate am inotransferase) followed by oxidative decarboxylation (arogenate dehydrogenase). High activity of arogenate dehydrogenase was found in extracts of etiolated sorghum seedlings, while no evidence of prephenate dehydrogenase was observed. Arogenate dehydrogenase from sorghum eluted, with high recovery of activity (93%), as a single peak on DEAE-cellulose chromatography. The enzyme was strongly inhibited by tyrosine but was unaffected by phenylala­nine, prephenate, or tryptophan. Kinetic analysis showed that tyrosine inhibition was competitive with arogenate and that the Ki for tyrosine (61 μm) was much smaller than the Km for arogenate (350 μm). The properties of arogenate dehydrogenase indicate that this enzyme is important in the regula­tion of tyrosine biosynthesis in sorghum. Strong inhibition of the enzyme by tyrosine may indicate that arogenate is a branch point in the shikimate pathway in plants and therefore arogenate may be a precursor to phenylalanine and the numerous phenylpropanoid secondary metabolites deriv­ed from phenylalanine.

scholarly journals Structure analysis of geranyl pyrophosphate methyltransferase and the proposed reaction mechanism of SAM-dependentC-methylation

2012 ◽  
Vol 68 (11) ◽  
pp. 1558-1569 ◽  
Author(s):  
Orapin Ariyawutthiphan ◽  
Toyoyuki Ose ◽  
Atsushi Minami ◽  
Sandip Sinde ◽  
Muneya Tsuda ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Enzymatic Reaction ◽  
Mycolic Acid ◽  
Isoprenoid Biosynthesis ◽  
Biosynthesis Pathway ◽  
Enzymatic Methylation ◽  
The Common ◽  
Dimethylallyl Pyrophosphate ◽  
Geranyl Pyrophosphate ◽  
Methyl Group Transfer

In the typical isoprenoid-biosynthesis pathway, condensation of the universal C5-unit precursors isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) occursviathe common intermediates prenyl pyrophosphates (C10–C20). The diversity of isoprenoids reflects differences in chain length, cyclization and further additional modification after cyclization. In contrast, the biosynthesis of 2-methylisonorneol (2-MIB), which is responsible for taste and odour problems in drinking water, is unique in that it primes the enzymatic methylation of geranyl pyrophosphate (GPP) before cyclization, which is catalyzed by anS-adenosyl-L-methionine-dependent methyltransferase (GPPMT). The substrate of GPPMT contains a nonconjugated olefin and the reaction mechanism is expected to be similar to that of the steroid methyltransferase (SMT) family. Here, structural analysis of GPPMT in complex with its cofactor and substrate revealed the mechanisms of substrate recognition and possible enzymatic reaction. Using the structures of these complexes, methyl-group transfer and the subsequent proton-abstraction mechanism are discussed. GPPMT and SMTs contain a conserved glutamate residue that is likely to play a role as a general base. Comparison with the reaction mechanism of the mycolic acid cyclopropane synthase (MACS) family also supports this result. This enzyme represented here is the first model of the enzymaticC-methylation of a nonconjugated olefin in the isoprenoid-biosynthesis pathway. In addition, an elaborate system to avoid methylation of incorrect substrates is proposed.

Arylation of enelactams using TIPSOTf: reaction scope and mechanistic insight

2021 ◽  
Author(s):  
Tomasz J. Idzik ◽  
Zofia M. Myk ◽  
Łukasz Struk ◽  
Magdalena Perużyńska ◽  
Gabriela Maciejewska ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Multinuclear Nmr ◽  
Mechanistic Insight ◽  
Nmr Study ◽  
Wide Range

Triisopropylsilyltrifluoromethanesulfonate can be effectively used for the arylation of a wide range of enelactams. The multinuclear NMR study provided deep insights into the reaction mechanism.

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