Impact of Effectors on the Catalytic Activity of Galactonolactone Oxidase from <i>Trypanosoma cruzi</i>

The influence of the structure of the effectors, 1,4-benzoquinone, coenzymes Q and their structural analogues, on the activity of galactonolactone oxidase from Trypanosoma cruzi (TcGAL) and the homologous enzyme L-galactono-1,4-lactone dehydrogenase from Arabidopsis thaliana (AtGALDH) was studied. Using two forms of AtGALDH, natural (dehydrogenase) and mutant (exhibiting oxidase activity), the role of 1,4-benzoquinone and its analogs as electron acceptors of AtGALDH and TcGAL was revealed. It has been established that compounds containing methoxy groups are more effective electron acceptors for TcGAL (coenzyme Q0, 2,6-dimethoxy-1,4-benzoquinone) compared to compounds without OCH3 groups (2,5-dihydroxy-1,4-benzoquinone). Using 2,6-dimethoxy-1,4-benzoquinone as an electron acceptor, an approach to the spectrophotometric measurement of TcGAL activity by changes in the absorption of the electron acceptor in the absence of additional components (a dye that becomes colorless when interacting with the reaction product, ascorbate) is proposed. The results obtained allow for a more targeted search for TcGAL inhibitors, which can be considered as the basis for the development of selective drugs against Chagas disease caused by T. cruzi.