|Gene:||prpD||Accession Number: G-10383 (MetaCyc)|
The prpD gene from Salmonella enterica enterica serovar Typhimurium was cloned and overexpressed in Escherichia coli, and the recombinant protein was purified and characterized. 2-methylcitrate dehydratase activity was demonstrated in vitro [Horswill01].
The authors reported that purified PrpD enzyme did not contain an iron-sulfur center, and displayed no requirements for metal cations. This contrasts with sequence analysis which predicts that the protein sould contain one 2Fe-2S cluster.
Gene Citations: [Horswill97]
Molecular Weight of Polypeptide: 53.787 kD (from nucleotide sequence), 54.0 kD (experimental) [Horswill01 ]
Enzymatic reaction of: 2-methylcitrate dehydratase
Synonyms: 2-hydroxybutane-1,2,3-tricarboxylate hydro-lyase
EC Number: 22.214.171.124
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.
This reaction is reversible.
In Pathways: 2-methylcitrate cycle I
The purified enzyme had a specific activity of 2.8 μmol/min/mg protein. However, this value may be an underestimate of the dehydration rate of the substrate if the enzyme uses as substrate only one of the four 2-methylcitrate stereoisomers thatwere present in the mixture, or if any of the stereoisomers inhibited enzyme activity [Horswill01].
Horswill01: Horswill AR, Escalante-Semerena JC (2001). "In vitro conversion of propionate to pyruvate by Salmonella enterica enzymes: 2-methylcitrate dehydratase (PrpD) and aconitase Enzymes catalyze the conversion of 2-methylcitrate to 2-methylisocitrate." Biochemistry 40(15);4703-13. PMID: 11294638
Horswill97: Horswill AR, Escalante-Semerena JC (1997). "Propionate catabolism in Salmonella typhimurium LT2: two divergently transcribed units comprise the prp locus at 8.5 centisomes, prpR encodes a member of the sigma-54 family of activators, and the prpBCDE genes constitute an operon." J Bacteriol 179(3);928-40. PMID: 9006051
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