Chemical Mechanism of the Branched-Chain Aminotransferase IlvE from Mycobacterium tuberculosis.

ABSTRACT: The biosynthetic pathway of the branched-chain amino acids is essential for Mycobacterium tuberculosis growth and survival. We report here the kinetic and chemical mechanism of the pyridoxal 5'-phosphate (PLP)-dependent branched-chain aminotransferase, IlvE, from M. tuberculosis (MtIlvE). This enzyme is responsible for the final step of the synthesis of the branched-chain amino acids isoleucine, leucine, and valine. As seen in other aminotransferases, MtIlvE displays a ping-pong kinetic mechanism. pK values were identified from the pH dependence on V as well as V/K, indicating that the phosphate ester of the PLP cofactor, and the α-amino group from l-glutamate and the active site Lys₂₀₄, play roles in acid-base catalysis and binding, respectively. An intrinsic primary kinetic is

SUBMITTER: Amorim Franco TM 

PROVIDER: S-EPMC5443349 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature