of poly-γ-glutamate biosynthesis by a Gram ..

Proteome analysis of metabolically engineered Escherichia coli producing poly(3-hydroxybutyrate).

MetaCyc superpathay of heme biosynthesis from glutamate


Histidine is derived from three precursors (Fig. 15–8): PRPP contributesfive carbons, the purine ring of ATP contributes a nitrogen and a carbon, andglutamine supplies the second ring nitrogen. The key steps are condensation ofATP and PRPP, in which N-1 of the purine ring is linked to the activated C-1 ofthe ribose of PRPP (step 1); purine ring opening that ultimately leaves N-1 andC-2 of adenine linked to the ribose (step 3); and formation of the imidazolering, a reaction in which glutamine donates a nitrogen (step 5). The use of ATPas a metabolite rather than a high-energy cofactor is unusual— but not wasteful,because it dovetails with the purine biosynthetic pathway. The remnant of ATPthat is released after the transfer of N-1 and C-2 is5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an intermediate of purinebiosynthesis that is rapidly recycled to ATP.

Biosynthesis of poly( 4-hydroxybutyric acid) by recombinant strains of Escherichia coli.

Amino acid synthesis - Wikipedia

So, the synthesis of asparagine is intrinsically tied to that of glutamine,and it turns out that glutamine is the amino group donor in the formation ofnumerous biosynthetic products, as well as being a storage form of NH3. Therefore, one would expect that glutamine synthetase, the enzyme responsiblefor the amidation of glutamate, plays a central role in the regulation ofnitrogen metabolism. We will now look into this control in more detail, beforeproceeding to the biosynthesis of the remaining nonessential amino acids.

Molecular mass of poly[(R)-3-hydroxybutyric acid] produced in a recombinant Escherichia coli.

Plants and bacteria synthesize all 20 common amino acids. Mammals cansynthesize about half; the others are required in the diet (essential aminoacids). Among the nonessential amino acids, glutamate is formed byreductive amination of α-ketoglutarate and serves as the precursor of glutamine,proline, and arginine. Alanine and aspartate (and thus asparagine) are formedfrom pyruvate and oxaloacetate, respectively, by transamination. The carbonchain of serine is derived from 3-phosphoglycerate. Serine is a precursor ofglycine; the β-carbon atom of serine is transferred to tetrahydrofolate. Inmicroorganisms, cysteine is produced from serine and from sulfide produced bythe reduction of environmental sulfate. Mammals produce cysteine from methionineand serine by a series of reactions requiring S-adenosylmethionine andcystathionine. Among the essential amino acids, the aromatic amino acids(phenylalanine, tyrosine, and tryptophan) form by a pathway in which chorismateoccupies a key branch point. Phosphoribosyl pyrophosphate is a precursor oftryptophan and histidine. The pathway to histidine is interconnected with thepurine synthetic pathway. Tyrosine can also be formed by hydroxylation ofphenylalanine (and thus is considered conditionally essential). The pathways forthe other essential amino acids are complex. The amino acid biosyntheticpathways are subject to allosteric end-product inhibition; the regulatory enzymeis usually the first in the sequence. Regulation of the various syntheticpathways is coordinated.

coli wall peptidoglycan; (b) utilizes the glutamate-amidated tetrapeptide as an acceptor.


Nitrogen Metabolism and the Urea Cycle

N2 - Pyrroline-5-carboxylate, an intermediate in the biosynthesis and degradation of glutamate, proline, and ornithine, acts as a strong reversible inhibitor of glucosamine-6-phosphate synthase, competitive with respect to glutamine. Proton magnetic resonance spectroscopy shows that, under these conditions, pyrroline-5-carboxylate exists in rapid equilibrium with glutamate γ-semialdehyde (0.05%). The observed variation of Ki with pH is consistent with inhibition by this rare species. Glutamate γ-semialdehyde is expected to react reversibly with a cysteine residue at the active site, identified by earlier inactivation studies, to form an analogue of a tetrahedral intermediate in glutamine hydrolysis. The apparent Ki value of glutamate γ-semialdehyde is approximately 3 × 10-8 M.

Reverse Translate - Bioinformatics

AB - Pyrroline-5-carboxylate, an intermediate in the biosynthesis and degradation of glutamate, proline, and ornithine, acts as a strong reversible inhibitor of glucosamine-6-phosphate synthase, competitive with respect to glutamine. Proton magnetic resonance spectroscopy shows that, under these conditions, pyrroline-5-carboxylate exists in rapid equilibrium with glutamate γ-semialdehyde (0.05%). The observed variation of Ki with pH is consistent with inhibition by this rare species. Glutamate γ-semialdehyde is expected to react reversibly with a cysteine residue at the active site, identified by earlier inactivation studies, to form an analogue of a tetrahedral intermediate in glutamine hydrolysis. The apparent Ki value of glutamate γ-semialdehyde is approximately 3 × 10-8 M.

GPT Gene - GeneCards | ALAT1 Protein | ALAT1 Antibody

Recombinant Escherichia coli is one of the promising host strains for the economical production of PHAs, and has been extensively investigated for the process development.