7th International Symposium of Pharmaceutical Sciences
VII SICF
A novel target in Chagas disease is the leucil-aminopeptidase M17 of Trypanosoma cruzi (LAPTc). The objective of this work was to identify a potent inhibitor of LAPTc. The optimized LAPTc gene was synthesized and cloned in the vector pET-19b for its expression in Escherichia coli. The genetic construction pET-19brLAPTc allows an soluble and active production of rLAPTc in E. coli BL21(DE3)pLysS, by induction during 20 h at 25ºC with IPTG 1 mM. A level of expression of 12.53 % of the total cellular protein was obtained. The rLAPTc enzyme was purified in a single step by IMAC, exploiting the N-terminal tag of 10 His encoded by the vector. The recombinant protein was obtained with a 90 % of purity and a yield of 90 mg per liter of culture. The enzyme has an optimal pH of 9.0, and preference for Leup-nitroanilide among nine tested substrates (KMapp = 74 M, kcatap = 4.4 s-1, kcat/KM (ap) = 59,459 L mol-1 s-1). The optimal temperature is 50ºC, and the cations Mg2+, Cd2+, Ba2+, Ca2+ and Zn2+ at 4 mM inhibited the activity in a 60 % or more, but Mn2+ inhibited only a 15 % and Co2+ activated in a 40 %. The recombinant enzyme is insensitive toward the protease inhibitors PMSF, TLCK, E-64 and pepstatin A, but is inhibited by EDTA and bestatin. The enzymatic activity of rLAPTc on Leu-pNA was inhibited in the micromolar order by bestatin and a synthetic tetrazole-peptidomimetic. The last one has potentialities as an in vitro antichagasic agent.
A novel target in Chagas disease is the leucil-aminopeptidase M17 of Trypanosoma cruzi (LAPTc). The objective of this work was to identify a potent inhibitor of LAPTc. The optimized LAPTc gene was synthesized and cloned in the vector pET-19b for its expression in Escherichia coli. The genetic construction pET-19brLAPTc allows an soluble and active production of rLAPTc in E. coli BL21(DE3)pLysS, by induction during 20 h at 25ºC with IPTG 1 mM. A level of expression of 12.53 % of the total cellular protein was obtained. The rLAPTc enzyme was purified in a single step by IMAC, exploiting the N-terminal tag of 10 His encoded by the vector. The recombinant protein was obtained with a 90 % of purity and a yield of 90 mg per liter of culture. The enzyme has an optimal pH of 9.0, and preference for Leup-nitroanilide among nine tested substrates (KMapp = 74 M, kcatap = 4.4 s-1, kcat/KM (ap) = 59,459 L mol-1 s-1). The optimal temperature is 50ºC, and the cations Mg2+, Cd2+, Ba2+, Ca2+ and Zn2+ at 4 mM inhibited the activity in a 60 % or more, but Mn2+ inhibited only a 15 % and Co2+ activated in a 40 %. The recombinant enzyme is insensitive toward the protease inhibitors PMSF, TLCK, E-64 and pepstatin A, but is inhibited by EDTA and bestatin. The enzymatic activity of rLAPTc on Leu-pNA was inhibited in the micromolar order by bestatin and a synthetic tetrazole-peptidomimetic. The last one has potentialities as an in vitro antichagasic agent.
About The Speaker
Lic. Mirtha Elisa Aguado Casas