Together with the BBB and BCSFB transport characteristics and surface areas, the drug characteristics (lipophilicity, size, shape, charge, affinity for a transporter etc., Figure 2) determine the actual transport rate and extent.
In such a case of partial slippage; a situation known to exist, for example, in mutants of CLC transporters, the actual mechanism of transport would be identical for both di- and tripeptides, and so it would be invalid to tout this as an example of "one transporter, two mechanisms".
"The actual thief, then the transporter, then the first middleman, then the second, main middleman, then the packer who does the packaging in Delhi, then the exporter, then Ghiya".
Except for levels (expressed per mg of total protein) of the active transporters, the actual absorption also depends on the surface areas of the different segments.
The uptake of any tracer depends on tracer delivery (perfusion) and actual uptake in cells (transporters).
We note that the actual selection for improved transporters was carried out in small volumes of liquid media, which we think could easily be scaled up.
Tracer experiments were conducted with N and C to determine rates at which N- and C-containing compounds were being assimilated by Microcystis and assess the relationship between transcript abundance of specific transporters and actual uptake rates.
Hence, the maximal FRET signal in the translocation assay reflects the actual amount of (active) transporters in the system, thus explaining the increased FRET signal for membranes with increased levels of FtsW and decreased FRET signal for membranes with depleted levels of FtsW.
Was its transporter actually a former prisoner?
The biological function of BBP-I is believed to be a general biotin transporter in plasma, whereas the actual deposition role in egg-yolk is reserved for BBP-II [ 3].
