Chorismate mutase from Escherichia coli

Enzymatic studies with chorismate mutase prephenate dehydrogenase from Escherichia coli show that the chorismate prephenate analog 7 is not a substrate for chorismate mutase65. Both 7 and 8 are moderately competitive inhibitors for chorismate mutase. Ester derivatives 4 and 5, as well as 6, readily undergo Claisen rearrangements in organic solvents. 

Baldwin, G. S. and B. E, Davidson, Kinetic studies on the mechanism of chorismated mutase/prephenate dehydratase from Escherichia coli, Biochim. Biophys. Acta, 742, 374-383 (1983). 

EcCM Escherichia coli chorismate mutase from P-protein... 

In Escherichia coli. Salmonella typhimurium and Aerobacter aerogenes two soluble multi-activity enzymes or enzyme complexes function in the utilisation of chorismate (14) for L-phenyl-alanine and L-tyrosine synthesis An enzyme or enzyme complex (P-protein) containing chorismate mutase and prephenate dehydratase activities has been isolated and partially purified from Escherichia coli. Salmonella typhimurium and Aerobacter aerogenes. The enzyme complex catalyses the transformation of chorismate (14) to phenylpyruvate (32) and both enzymic activities are retained in physical association after chromatography on DEAE cellulose. Kinetic analysis indicated that in isolated enzyme systems direct synthesis of phenylpyruvate (32) from chorismate (14) does not occur. Prephenate (31) once formed dissociates from the enzyme surface and accumulates in the reaction medium. After a lag period it is converted to phenylpyruvate (32). Schmit, Artz and Zalkin also obtained evidence to show that functionally distinct sites (catalytic and regulatory) exist on the P-protein from Salmonella typhimurium for chorismate mutase and prephenate dehydratase activities. The P-protein was obtained from Escherichia coli K-12 by Davidson, Blackburn and Dopheide who showed that it existed in solution mainly as a dimer of similar (and probably identical) sub-units of... 

Chavez-Bejar, M.l. et al (2008) Metabolic engineering of Escherichia coli for L-tyrosine production by expression of genes coding for the chorismate mutase domain of the native chorismate mutase-prephenate dehydratase and a cyclohexadienyl dehydrogenase from Zymomonas... 

In other organisms which have been examined the situation is different from that observed in Escherichia coli and Aerobacter aerogenes. Thus in Neurospora crassa a single chorismate mutase was found, uncomplexed with either of the prephenate utilising enzymes On the other hand two chorismate mutases were found in yeast but both of these were readily separable from the corresponding prephenate dehydratase and prephenate dehydrogenase activities. 

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