The prephenate dehydrogenase component of the bifunctional T‐protein in enteric bacteria can utilize L‐arogenate

Abstract

The prephenate dehydrogenase component of the bifunctional T‐protein (chorismate mutase:prephenate dehydrogenase) has been shown to utilize L‐arogenate, a common precursor of phenylalanine and tyrosine in nature, as a substrate. Partially purified T‐protein from Klebsiella pneumoniae and from Escherichia coli strains K12, B, C and W was used to demonstrate the utilization of L‐arogenate as an alternative substrate for prephenate in the presence of nicotinamide adenine dinucleotide as cofactor. The formation of L‐tyrosine from L‐arogenate by the T‐protein dehydrogenase was confirmed by high‐performance liquid chromatography. As expected of a common catalytic site, dehydrogenase activity with either prephenate or L‐arogenate was highly sensitive to inhibition by L‐tyrosine.