Fluctuations in the metabolism and transport of arginine during the Trypanosoma cruzi life cycle

ALONSO, GUILLERMO; PEREIRA, CLAUDIO; IVALDI, SOLEDAD; BOUVIER, LEÓN ALBERTO; FLAWIA, MIRTHA; TORRES, HECTOR

Cordoba, Argentina

Congreso; XXXVII Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular ? SAIB; 2001

Arginine kinase (E.C. 2.7.3.3) catalyzes the synthesis of the phosphagen phosphoarginine, which play a critical role as energy reserve because its high-energy phosphate can be transferred when a renewal of ATP is needed. It has been postulated that phosphoarginine supports bursts of cellular activity until catabolic events such as glycogenolysis, glycolysis and oxidative pltosphorylation are switched on. In epimastigotes of Trypanosoma cruzi, the etiological agent of Chagas´ disease, arginine kinase activity increased about seven fold during the exponential phase of growth. A correlation between growth rate, enzyme-specific activity and enzyme protein was observed up to 18 days of culture. During the same time the transport of arginine decreases continuously reaching a minimal value at the 14 day. Furthermore, treating 3-day cultures with a conditioned media from 18 days cultures can reproduce both effects. When the arginine kinase activity and arginine transport are assayed in trypomastigotes from cell cultures, the values obtained resemble those found in epimastigotes cultured for more than 14 days. For this reason we propose that arginine kinase activity could be involved in the management of energy reserves during starvation or under nutritional stress conditions. Moreover the arginine kinase activity together with the arginine transport can be used as differentiation markers. Supported by CONICET, UBA and FONCYT