INTERACCION DE LA GLUTAMINA SINTETASA (GS) Y EL PEPTIDO [beta] -AMILOIDE COMO UNA ESTRATEGIA DE PURIFICACION

Alzheimers disease (AD) is the most common form of dementia in adulthood; it is manifested by the progressive loss of memory since neurons in both cerebral cortex and hippocampus die. In all the forms of AD is observed the increased expression of different proteins, as well as the presence of insoluble aggregates of -amyloid peptide (BAP). Glutamine synthetase (GS) is a key enzyme in the metabolism of glutamate and in the detoxication of ammonium (NH4+). A possible interaction GS-PBA has been previously reported and it can be associated with AD. In this work we performed the purication of the enzyme from rat brain extract subjected to fractional precipitation 20-60 % saturation with (NH4)2SO4, and thereafter through successive chromatographies of gel ltration, ion exchange and afnity. The molecular weight of the complex was calculated at 137 kDa by the order of elution in the column ltration. The interaction of the enzyme with 1-40 PBA was identied, achieving the purication of a single band of 45 kDa corresponding to the monomeric form of the GS. In this paper we present a new method of the enzyme purication and we demonstrated the interaction of GS with the PBA. We propose this interaction GS-PBA can be one of the processes that occur in the disease and it could explain the reduction in enzyme activity in patients with AD, since it might alter the glutamate-gluta-mine cycle and generate changes in the cellular environment which favor gluta-mate excitotoxicity typical of neurode-generation processes.