61 research outputs found
Evidence for tripeptide/H+ co-transport in rabbit renal brush-border membrane vesicles
Expression and protein kinase C-dependent regulation of peptide/H+ co-transport system in the Caco-2 human colon carcinoma cell line
Reconstitution of the human placental 5-hydroxytryptamine transporter in a catalytically active form after detergent solubilization
Characterization of an ATP-driven H+ pump in human placental brush-border membrane vesicles
Evidence for histidyl and carboxy groups at the active site of the human placental Na+-H+ exchanger
Transport of taurine and its regulation by protein kinase C in the JAR human placental choriocarcinoma cell line
Sodium-gradient-driven, high-affinity, uphill transport of succinate in human placental brush-border membrane vesicles
Functional characterization and chromosomal localization of a cloned taurine transporter from human placenta
Kinetic Measurements of Di- and Tripeptide and Peptidomimetic Drug Transport in Different Kidney Regions Using the Fluorescent Membrane Potential-Sensitive Dye, DiS-C3-(3).
Tri- and dipeptides are transported in the kidney by PEPT1 and PEPT2 isoforms. The aim of this study was to investigate differences in transport kinetics between renal brush border (BBMV) and outer medulla (OMMV) membrane vesicles (where PEPT1 and PEPT2 are sequentially available) for a range of di- and tripeptides and peptidomimetic drugs. This was accomplished through the use of the potential-sensitive fluorescent dye 3,3'-dipropylthiacarbocyanine iodide [DiS-C3-(3)]. BBMV and OMMV were prepared from the rat kidney using standard techniques. The presence of PEPT1 in BBMV and PEPT2 in OMMV was confirmed using Western blotting. Fluorescence changes were measured when extravesicular medium at pH 6.6 containing 0-1 mM substrates was added to a cuvette containing vesicles pre-equilibrated at pH 7.4 and 2.71 μM DiS-C3-(3). An increase in fluorescence intensity occurred upon substrate addition reflecting the expected positive change in membrane potential difference. Of the range of substrates studied, OMMV manifested the highest affinity to cefadroxil and valacyclovir (K m 4.3 ± 1.2 and 11.7 ± 3.2 µM, respectively) compared to other substrates, whilst the BBMV showed a higher affinity to Gly-His (K m 15.4 ± 3.1 µM) compared to other substrates. In addition, OMMV showed higher affinity and capacity to Gly-Gln (K m 47.1 ± 9.8 µM, 55.5 ± 2.8 ΔF/s/mg protein) than BBMV (K m 78.1 ± 13.3 µM and 35.5 ± 1.7 ΔF/s/mg protein, respectively). In conclusion, this study successfully separated the expression of PEPT1 and PEPT2 into different vesicle preparations inferring their activity in different regions of the renal proximal tubule
Redução da proteÃna bruta e suplementação de aminoácidos para suÃnos machos castrados dos 30 aos 60 kg mantidos em ambiente de alta temperatura
- …