The Non-Canonical Substrates of Trypanosoma cruzi Tyrosine and Aspartate Aminotransferases: Branched-Chain Amino Acids

Autor(es)

Manchola, Nubia Carolina ^[1] ; Silber, Ariel Mariano ^[1] ; Nowicki, Cristina ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Ciencias Biomed, Lab Biochem Tryps LaBTryps, Ave Prof Lineu Prestes 1374, Sao Paulo - Brazil

^[2] Univ Buenos Aires, Fac Farm & Bioquim, CONICET, IQUIFIB, Junin 956, RA-1113 Buenos Aires, DF - Argentina

• Tipo de documento: Artigo Científico
• Fonte: Journal of Eukaryotic Microbiology; v. 65, n. 1, p. 70-76, JAN-FEB 2018.
• Citações Web of Science: 2

Resumo

Trypanosoma cruzi, the etiological agent of Chagas disease, lacks genes that encode canonical branched-chain aminotransferases. However, early studies showed that when epimastigotes were grown in the presence of C-14(1)-DL-leucine, the label was incorporated into various intermediates. More recently, our studies provided evidence that T.cruzi epimastigotes display a single ATP-dependent and saturable transport system that enables epimastigotes to uptake branched-chain amino acids (BCAAs) from the culture media. To extend our knowledge of the first step of BCAA catabolism, the ability of this parasite's noncanonical broad specificity aminotransferases, such as tyrosine aminotransferase (TAT) and aspartate aminotransferase (ASAT), to transaminate these amino acids was investigated. Indeed, our results show that TAT and ASAT utilize BCAAs as substrates; however, both enzymes differ in their catalytic competence in utilizing these amino donors. For instance, ASAT transaminates isoleucine nearly 10-fold more efficiently than does TAT. This unique characteristic of TAT and ASAT allows to explain how BCAAs can be oxidized in the absence of a BCAA transaminase in T. cruzi. (AU)

• Processo FAPESP: 13/18970-6 - Caracterização do efeito Disulfiram em Trypanosoma cruzi
• Beneficiário: Ariel Mariano Silber
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 16/06034-2 - O papel biológico de aminoácidos e seus metabólitos derivados em Trypanosoma cruzi
• Beneficiário: Ariel Mariano Silber
• Modalidade de apoio: Auxílio à Pesquisa - Temático