Table 2 Comparison of endogenous Xenopus laevis L-leucine transporter maximum turnover rates estimated using model input data from assays in various combinations of uptake buffers.

From: Quantifying the relative contributions of different solute carriers to aggregate substrate transport

 

Original

Test

Experimental buffer conditions used as model input

Leu+Na+

Leu+Na+free

Leu+Na++Ala+Arg Leu+Na++BCH

Leu+Na++BCH

Leu+Na+free+Ala

Leu+Na++Ala+Arg

Leu+Na++BCH

Leu+Na++BCH+Ala

Leu+Na+

Leu+Na++Ala+Arg

Leu+Na+free

Leu+Na+free+Ala

Vmax,xB0AT1

30.7 ± 5.1

28.2 ± 8.1

39.2 ± 4.3

27.9 ± 4.8

34.3 ± 2.5

Vmax,xLAT4

383.4 ± 8.7

405.3 ± 16.6

372.1 ± 8.2

406.5 ± 9.4

382.0 ± 3.2

  1. Results are amino acid transporter maximum transport rates (normalized to uptake rate at 1 mM Leu in +Na+ buffer) with standard deviations (Vmax,i ± SD). The model estimations were calculated using data generated from different combinations of uptake buffers as indicated in the column headings. Data generated from assays in the “Original” buffer combination was used for model estimations of Vmax . The dependence of the model calculations on the data from different buffer combinations used as input was probed using the “Test” buffer combinations. The mean Vmax,i ±SEM for the four “Test” buffer combinations is 32.4 ± 2.7 for xB0AT1 and 391.5 ± 5.2 for xLAT4.
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