title: Aspartate aminotransferases ofPanicum miliaceum L. andPanicum antidotale retz. : Inactivation and reconstitution.
abstract: L-Aspartate: 2-oxoglutarate transaminase was isolated and partially purified from leaves ofPanicum miliaceum (C4, NAD-malic enzyme type) and ofPanicum antidotale (C4, NADP-malic enzyme type). In each preparation two isoenzymes with different kinetic properties could be characterized. The enzyme activity was irreversibly inhibited by 2-aminooxyacetic acid and by 2-amino-4-methoxy-3-butenoic acid. The first inhibitor reacted with pyridoxal 5-phosphate, and its inhibition could be reversed by the exchange of the modified coenzyme. The second inhibitor binds not only to the coenzyme pyridoxal 5-phosphate, but also to the apoprotein. The results of the dissociation and reconstitution experiments were in agreement with the kinetic data, showing that the mode of inactivation was different for 2-aminooxyacetic acid and 2-amino-4-methoxy-3-butenoic acid.
authors.affiliation: Abteilung Biologie der Ruhr-Universität, Lehrstuhl für Biochemie der Pflanzen, D-4630, Bochum 1, Federal Republic of Germany.
authors.forename: C
authors.initials: C
authors.lastname: Balkow
authors.forename: G F
authors.initials: GF
authors.lastname: Wildner