INTERACTION BETWEEN GLUTAMATE SYNTHASE AND FERREDOXIN FROM MONORAPHIDIUM-BRAUNII - CHEMICAL MODIFICATIONS AND CROSS-LINKING STUDIES

Incubation of ferredoxin and glutamate synthase (EC 1.4.7.1) from the eukaryotic microalgae Monoraphidium braunii, in the presence of the ca rboxyl group activator, N-ethyl-3-(3-dimethylaminopropyl)-carbodiimide , led to the formation of a functional Fd:GOGAT covalent complex. The experiments showed that glutamate synthase has two active sites for el ectrostatically binding ferredoxin during the enzyme catalytic cycle. Ferredoxin carboxyl groups and glutamate synthase lysyl and also argin yl residues are involved in the active complex formation.