scholarly journals Pyruvate metabolism by aminopterin-inhibited Aerobacter aerogenes

1968 ◽  
Vol 106 (2) ◽  
pp. 367-373 ◽  
Author(s):  
M. Webb
Keyword(s):  
Reductive Amination ◽  
Exponential Phase ◽  
Carboxyl Group ◽  
Keto Acid ◽  
Secondary Products ◽  
Oxidative Deamination ◽  
Pyruvate Metabolism ◽  
Early Exponential Phase ◽  
Aerobacter Aerogenes ◽  
Acid Precursor

1. The synthesis and utilization of both alanine (by reductive amination, oxidative deamination and transamination) and valine (by transamination only) in Aerobacter aerogenes are unaffected by aminopterin. These amino acids, which accumulate in aminopterin-treated cultures of this organism, are therefore considered to be formed as secondary products from the excess of pyruvate that also accumulates. 2. Oxidative metabolism of pyruvate and the synthesis of acetylmethylcarbinol by A. aerogenes cells are unaltered by growth in the presence of aminopterin. 3. Cells from static and anaerobic cultures that have been treated with the folic acid antagonist in the early exponential phase have a decreased ability to cleave pyruvate to acetate and formate, and to effect the exchange of formate with the carboxyl group of pyruvate. 4. 3-Methyl-2-oxobutanoate, the keto acid precursor of valine, cannot replace pyruvate as substrate in either the phosphoroclastic or the exchange reaction.

Properties of NAD-dependent glutamate dehydrogenase from the tylosin producer Streptomyces fradiae

1997 ◽  
Vol 43 (11) ◽  
pp. 1005-1010 ◽  
Author(s):  
Kien Trung Nguyen ◽  
Lieu Thi Nguyen ◽  
Jan Kopecký ◽  
Vladislav Běhal
Keyword(s):  
Key Words ◽  
Glutamate Dehydrogenase ◽  
Reductive Amination ◽  
Divalent Cations ◽  
Ammonium Assimilation ◽  
Alkaline Ph ◽  
Streptomyces Fradiae ◽  
Oxidative Deamination

Glutamate dehydrogenase is an enzyme responsible for ammonium assimilation and glutamate catabolism in organisms. The tylosin producer Streptomyces fradiae possesses both NADP- and NAD-dependent glutamate dehydrogenases. The latter enzyme was purified 498-fold with a 7.5% recovery by a six-step protocol. The enzyme is composed of two subunits, each of Mr 47 000, and could form active aggregates of four or eight subunits. Its activity was inactivated by alkaline pH or temperatures of −20 °C or above 40 °C. Activities assayed in the direction of oxidative deamination and reductive amination were optimal at pH 9.2 and 8.8, respectively, and at temperatures of 30–35 °C. No activity was found when NAD(H) was replaced with NADP(H). The Km values were 32.2 mM for L-glutamate, 0.3 mM for NAD+, 3.4 mM for 2-ketoglutarate, 14.2 mM for NH4+, and 0.05 mM for NADH. Deamination activity was partially inhibited by adenyl nucleotides and several divalent cations; amination activity was not affected by the nucleotides but significantly inhibited by Cu2+ or Ni2+.Key words: Streptomyces fradiae, NAD-dependent glutamate dehydrogenase, purification, properties.

scholarly journals Analysis of Dibenzothiophene Desulfurization in a Recombinant Pseudomonas putida Strain

2008 ◽  
Vol 75 (3) ◽  
pp. 875-877 ◽  
Author(s):  
Javier Calzada ◽  
Mar�a T. Zamarro ◽  
Almudena Alc�n ◽  
Victoria E. Santos ◽  
Eduardo D�az ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Exponential Growth ◽  
Exponential Phase ◽  
Cell Process ◽  
Growth Phases ◽  
Early Exponential Phase ◽  
Sharp Maximum ◽  
Resting Cell

ABSTRACT Biodesulfurization was monitored in a recombinant Pseudomonas putida CECT5279 strain. DszB desulfinase activity reached a sharp maximum at the early exponential phase, but it rapidly decreased at later growth phases. A model two-step resting-cell process combining sequentially P. putida cells from the late and early exponential growth phases was designed to significantly increase biodesulfurization.

A new retro-aza-ene reaction: formal reductive amination of an α-keto acid to an α-amino acid

Tetrahedron ◽  
1992 ◽  
Vol 48 (9) ◽  
pp. 1715-1728 ◽  
Author(s):  
David B. Berkowitz ◽  
W. Bernd Schweizer
Keyword(s):  
Amino Acid ◽  
Reductive Amination ◽  
Keto Acid ◽  
Ene Reaction

THE ANAEROBIC DISSIMILATION OF D-GLUCOSE-1-C14, D-ARABINOSE-1-C14, AND L-ARABINOSE-1-C14 BY AEROBACTER AEROGENES

1954 ◽  
Vol 32 (1) ◽  
pp. 147-153 ◽  
Author(s):  
A. C. Neish ◽  
F. J. Simpson
Keyword(s):  
Carbon Dioxide ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Carboxyl Groups ◽  
Methyl Groups ◽  
Carboxyl Group ◽  
Complete Conversion ◽  
Aerobacter Aerogenes ◽  
Methyl Group ◽  
Ethanol Acetic Acid

D-Glucose-1-C14, D-arabinose-1-C14, and L-arabinose-1-C14 were dissimilated anaerobically by Aerobacter aerogenes. The major products (2,3-butanediol, ethanol, acetic acid, lactic acid, formic acid, and carbon dioxide) were isolated and the location of C14 determined. The products from glucose were all labeled, mainly in the methyl groups, in agreement with the hypothesis that they were derived from methyl-labeled pyruvate formed by the reactions of the classical Embden–Meyerhof scheme for glycolysis. The products from both pentoses appeared to have been formed from pyruvate labeled in both the methyl and carboxyl groups with twice as much C14 in the methyl group as in the carboxyl group. This result may be explained quantitatively by a hypothesis assuming complete conversion of pentose to triose via a heptulose.

3-(4-Oxocyclohexyl)propionic acid monohydrate: hydrogen bonding in the hydrate of a ζ-keto acid

2007 ◽  
Vol 63 (3) ◽  
pp. o1173-o1175
Author(s):  
Stephanie M. Witko ◽  
Mark Davison ◽  
Hugh W. Thompson ◽  
Roger A. Lalancette
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Water Molecule ◽  
Carboxyl Group ◽  
Keto Acid ◽  
Carbonyl Groups ◽  
O 178 ◽  
Network Of Hydrogen Bonds

In the title crystal structure, C9H14O3·H2O, the water molecule accepts a hydrogen bond from the carboxyl group [O...O = 2.6004 (13) Å and O—H...O = 163°], while donating hydrogen bonds to the ketone [O...O = 2.8193 (14) Å and O—H...O = 178 (2)°] and the acid carbonyl groups [O...O = 2.8010 (14) Å and O—H...O = 174 (2)°]. This creates a network of hydrogen bonds confined within a continuous flat ribbon two molecules in width and extending in the [101] direction.

scholarly journals Regulation of d-Aspartate Oxidase Gene Expression by Pyruvate Metabolism in the Yeast Cryptococcus humicola

2021 ◽  
Vol 9 (12) ◽  
pp. 2444
Author(s):  
Daiki Imanishi ◽  
Sota Zaitsu ◽  
Shouji Takahashi
Keyword(s):  
Gene Expression ◽  
Growth Retardation ◽  
Wild Type Strain ◽  
Transcriptional Level ◽  
Oxidative Deamination ◽  
Pyruvate Metabolism ◽  
Oxidase Gene ◽  
Cryptococcus Humicola ◽  
In The Wild

d-Aspartate oxidase (DDO) is a peroxisomal flavoenzyme that catalyzes the oxidative deamination of acidic d-amino acids. In the yeast Cryptococcus humicola strain UJ1, the enzyme ChDDO is essential for d-Asp utilization and is expressed only in the presence of d-Asp. Pyruvate carboxylase (Pyc) catalyzes the conversion of pyruvate to oxaloacetate and is involved in the import and activation of certain peroxisomal flavoenzymes in yeasts. In this study, we analyzed the role of Pyc in the expression of ChDDO gene in C. humicola strain UJ1. PYC gene disruption (∆Chpyc1) in strain UJ1 resulted in growth retardation on glucose and NH4Cl medium. The growth was restored by supplying oxaloacetate from l-Asp or α-ketoglutarate by a transaminase. On the other hand, the supply of oxaloacetate from d-Asp by ChDDO was not able to prevent growth retardation because of a significant decrease in ChDDO gene expression at the transcriptional level. The addition of pyruvate significantly decreased ChDDO gene transcription in the ∆Chpyc1 strain but increased the same in the wild-type strain, even though the intracellular pyruvate content was similar in both strains. These results suggest that ChDDO gene expression might be regulated by pyruvate metabolism, as well as by the presence of d-Asp.

scholarly journals Anticonvulsant Drugs, Brain Glutamate Dehydrogenase Activity and Oxygen Consumption

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Lourdes A. Vega Rasgado ◽  
Guillermo Ceballos Reyes ◽  
Fernando Vega-Díaz
Keyword(s):  
Oxygen Consumption ◽  
Glutamate Dehydrogenase ◽  
Reductive Amination ◽  
Pyridoxal Phosphate ◽  
Neuronal Excitability ◽  
Aminooxyacetic Acid ◽  
Oxidative Deamination ◽  
Key Enzyme

Glutamate dehydrogenase (GDH, E.C. 1.4.1.3.) is a key enzyme for the biosynthesis and modulation of glutamate (GLU) metabolism and an indirect γ-aminobutyric acid (GABA) source, here we studied the effect of anticonvulsants such as pyridoxal phosphate (PPAL), aminooxyacetic acid (AAOA), and hydroxylamine (OHAMINE) on GDH activity in mouse brain. Moreover, since GLU is a glucogenic molecule and anoxia is a primary cause of convulsions, we explore the effect of these drugs on oxygen consumption. Experiments were performed in vitro as well as in vivo for both oxidative deamination of GLU and reductive amination of α-ketoglutarate (αK). Results in vitro showed that PPAL decreased oxidative deamination of GLU and oxygen consumption, whereas AAOA and OHAMINE inhibited GDH activity competitively and also inhibited oxygen consumption when αK reductive amination was carried out. In contrast, results showed that in vivo, all anticonvulsants enhanced GLU utilization by GDH and also decreased oxygen consumption. Together, results suggest that GDH activity has repercussions on oxygen consumption, which may indicate that the enzyme activity is highly regulated by energy requirements for metabolic activity. Besides, GDH may participate in regulation of GLU and, indirectly GABA levels, hence in neuronal excitability, becoming a key enzyme in seizures mechanism.

THE ANAEROBIC DISSIMILATION OF D-GLUCOSE-1-C14, D-ARABINOSE-1-C14, AND L-ARABINOSE-1-C14 BY AEROBACTER AEROGENES

1954 ◽  
Vol 32 (3) ◽  
pp. 147-153 ◽  
Author(s):  
A. C. Neish ◽  
F. J. Simpson
Keyword(s):  
Carbon Dioxide ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Carboxyl Groups ◽  
Methyl Groups ◽  
Carboxyl Group ◽  
Complete Conversion ◽  
Aerobacter Aerogenes ◽  
Methyl Group ◽  
Ethanol Acetic Acid

D-Glucose-1-C14, D-arabinose-1-C14, and L-arabinose-1-C14 were dissimilated anaerobically by Aerobacter aerogenes. The major products (2,3-butanediol, ethanol, acetic acid, lactic acid, formic acid, and carbon dioxide) were isolated and the location of C14 determined. The products from glucose were all labeled, mainly in the methyl groups, in agreement with the hypothesis that they were derived from methyl-labeled pyruvate formed by the reactions of the classical Embden–Meyerhof scheme for glycolysis. The products from both pentoses appeared to have been formed from pyruvate labeled in both the methyl and carboxyl groups with twice as much C14 in the methyl group as in the carboxyl group. This result may be explained quantitatively by a hypothesis assuming complete conversion of pentose to triose via a heptulose.

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