Blue-Green Bacteria synthesise L-Tyrosine by the Pretyrosine Pathway

Stenmark, Sherry L.; Pierson, Duane L.; Jensen, Roy A.; Glover, George I.

doi:10.1038/247290a0

Cited by 106 publications

(71 citation statements)

References 8 publications

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“…The biosynthesis of phenylalanine and tyrosine in Pseudornonas aeruginosa [27] and of tyrosine in bluegreen bacteria [28] occurs via pretyrosine which is formed by amino group transfer to prephenate. Thus it was of interest to determine if either of the aminotransferases was capable of catalyzing a transamination reaction between glutamate and prephenate.…”

Section: Discussionmentioning

confidence: 99%

The Purification and Properties of the Aspartate Aminotransferase and Aromatic‐Amino‐Acid Aminotransferase from Escherichia coli

Powell

Morrison

1978

European Journal of Biochemistry

105

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A simple and convenient procedure is described for the isolation in good yield of two aminotransferases from various strains of Escherichia coli. On the basis of their substrate specificities one of the enzymes has been classified as an aromatic amino acid aminotransferase and the other as an aspartate aminotransferase, but both act on a wide range of substrates. Pyridoxal phosphate is bound more strongly to the aspartate aminotransferase than to the aromatic amino transferase which cannot be fully re-activated after removal of the prosthetic group. Both enzymes are composed of two subunits which appear to be identical.In Escherichia coli, the biosynthesis of phenylalanine and tyrosine from chorismate proceeds via the reactions :Chorismate' \ prephenate --t 4-hydroxyphenylpyruvate + tyrosine.

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Section: Discussionmentioning

confidence: 99%

The Purification and Properties of the Aspartate Aminotransferase and Aromatic‐Amino‐Acid Aminotransferase from Escherichia coli

Powell

Morrison

1978

European Journal of Biochemistry

105

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“…The existence of an arogenate route for the biosynthesis of phenylalanine and/or tyrosine was first reported by Stenmark et al [5]. It was then shown mainly by the group of Jensen that depending on the organisms, dehydrogenases and dehydratases dedicated to tyrosine and phenylalanine biosyntheses, respectively, present different specificities for the cyclohexadienyl substrates arogenate or prephenate.…”

Section: Introductionmentioning

confidence: 99%

Identification of a plant gene encoding glutamate/aspartate‐prephenate aminotransferase: The last homeless enzyme of aromatic amino acids biosynthesis

et al. 2010

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Edited by Ulf-Ingo Flügge Keywords:Aspartate aminotransferase Aromatic amino acid Enzymology Metabolism Plant Prephenate aminotransferase a b s t r a c tIn all organisms synthesising phenylalanine and/or tyrosine via arogenate, a prephenate aminotransferase is required for the transamination of prephenate into arogenate. The identity of the gene encoding this enzyme in the organisms where this activity occurs is still unknown. Glutamate/aspartate-prephenate aminotransferase (PAT) is thus the last homeless enzyme in the aromatic amino acids pathway. We report on the purification, mass spectrometry identification and biochemical characterization of Arabidopsis thaliana prephenate aminotransferase. Our data revealed that this activity is housed by the prokaryotic-type plastidic aspartate aminotransferase (At2g22250). This represents the first identification of a gene encoding PAT.

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“…B. subtilis exemplifies organisms which synthesize L-tyrosine via 4-hydroxyphenylpyruvate [27, 281. Other organisms such as cyanobacteria and Brevibacterium synthesize L-tyrosine via L-arogenate [27,28]. P. aeruginosa can synthesize L-tyrosine by use of either 4-hydroxyphenylpyruvate or L-arogenate [l].…”

Section: Route To L-tyrosine Biosynthesis In Z Mobilismentioning

confidence: 99%

An allosterically insensitive class of cyclohexadienyl dehydrogenase from Zymomonas mobilis

Zhao

Xia

Ingram

et al. 1993

European Journal of Biochemistry

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The key enzyme of tyrosine biosynthesis in many Gram-negative prokaryotes is cyclohexadienyl dehydrogenase. The Zymomonas mobilis gene ( t y r o coding for this enzyme was cloned in Escherichia coli by camplementation of a tyrosine auxotroph. The tyrC gene was 882 bp long, encoding a protein with a calculated molecular mass of 32086 Da. The Z. mobilis cyclohexadienyl dehydrogenase expressed in E. coli was purified to electrophoretic homogeneity. The subunit molecular mass of the purified enzyme was 32kDa as determined by SDSPAGE. The ratio of the activity of arogenate dehydrogenase to that of prephenate dehydrogenase (approximately 3 : 1) remained constant throughout purification, and the two activities were therefore inseparable. The genetic and biochemical data obtained demonstrated a single enzyme protein capable of catalyzing either of two reactions. K, values of 0.25 mM and 0.18 mM were obtained for prephenate and L-arogenate, respectively. The K, value obtained for NAD+ (0.09 mM) was the same regardless of whether the enzyme was assayed as arogenate dehydrogenase or as prephenate dehydrogenase. Unlike the corresponding enzyme of Pseudomonas aemginosa or E. coli, the cyclohexadienyl dehydrogenase of Z. mobilis lacks sensitivity to feedback inhibition by L-tyrosine. A typical NAD+-binding domain was found to be located at the N-terminus of the protein.Although the deduced amino-acid sequence of the Z. mobilis cyclohexadienyl dehydrogenase showed relatively low identity (19-32 %) with the prephenate dehydrogenases of Bacillus subtilis and Saccharomyces cerevisiae, as well as with the cyclohexadienyl dehydrogenase components of the bifunctional T-proteins of E. coli and Erwinia herbicola, a presumptive motif was identified which may correspond to critical residues of the binding site for cyclohexadienyl substrate molecules.Immediately upstream of tyrC a portion of a gene was sequenced and found to exhibit clearcut homology of the deduced amino-acid sequence with the B. subtilis hzsH gene product. Thus, the Zymomonas gene organization is reminiscent of the linkage of genes encoding a tyrosine-pathway dehydrogenase and a histidine-pathway aminotransferase in B. subtilis.

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Blue-Green Bacteria synthesise L-Tyrosine by the Pretyrosine Pathway

Cited by 106 publications

References 8 publications

The Purification and Properties of the Aspartate Aminotransferase and Aromatic‐Amino‐Acid Aminotransferase from Escherichia coli

The Purification and Properties of the Aspartate Aminotransferase and Aromatic‐Amino‐Acid Aminotransferase from Escherichia coli

Identification of a plant gene encoding glutamate/aspartate‐prephenate aminotransferase: The last homeless enzyme of aromatic amino acids biosynthesis

An allosterically insensitive class of cyclohexadienyl dehydrogenase from Zymomonas mobilis

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