کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2437037 1107407 2006 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Biochemical characterization of the glutamate transport in Trypanosoma cruzi
موضوعات مرتبط
علوم زیستی و بیوفناوری ایمنی شناسی و میکروب شناسی انگل شناسی
پیش نمایش صفحه اول مقاله
Biochemical characterization of the glutamate transport in Trypanosoma cruzi
چکیده انگلیسی

The role of amino acids in trypanosomatids goes beyond protein synthesis, involving processes such as differentiation, osmoregulation and energy metabolism. The availability of the amino acids involved in those functions depends, among other things, on their transport into the cell. Here we characterize a glutamate transporter from the human protozoan parasite Trypanosoma cruzi. Kinetic data show a single saturable system with a Km of 0.30 mM and a maximum velocity of 98.34 pmoles min−1 per 2×107 cells for epimastigotes and 20 pmoles min−1 per 2×107 cells for trypomastigotes. Transport was not affected by parasite nutrient starvation for up to 3 h. Aspartate, alanine, glutamine, asparagine, methionine, oxaloacetate and α-ketoglutarate competed with the substrate in 10-fold excess concentrations. Glutamate uptake was strongly dependent on pH, but not on Na+ or K+ concentrations in the extracellular medium. These data were consistent with the sensitivity of the system to the H+ ionophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone, suggesting that transport is driven by H+ concentration gradient across the cytoplasmic membrane. The glutamate transport increased linearly with temperature in a range from 15 to 40 °C, allowing the calculation of an activation energy of 52.38 kJ/mol.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal for Parasitology - Volume 36, Issue 2, February 2006, Pages 157–163
نویسندگان
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