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BioAssay: AID 679427

TP_TRANSPORTER: uptake (pH 7.4) of Acetic acid at a concentration of 4.94 u M in OATP-B-expressing HEK293 cells

The pH-sensitive activity of human organic anion transporting polypeptide OATP-B, which is expressed at the apical membrane of human small intestinal epithelial cells, was functionally characterized. When initial uptake of estrone-3-sulfate, a typical substrate of OATP, was studied kinetically, we observed an increase in V(max) with decrease of pH from 7.4 to 5.0, whereas the change in K(m) was more ..
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AID: 679427
Data Source: ChEMBL (836566)
Depositor Category: Other
BioAssay Version:
Deposit Date: 2013-05-16
Modify Date: 2014-08-26

Data Table ( Complete ):           View All Data
Target
Sequence: RecName: Full=Solute carrier organic anion transporter family member 2B1; AltName: Full=Organic anion transporter B; Short=OATP-B; AltName: Full=Organic anion transporter polypeptide-related protein 2; Short=OATP-RP2; Short=OATPRP2; AltName: Full=Solute carrier family 21 member 9
Description ..   
Protein Family: KAZAL_SLC21
Comment ..   

Gene:SLCO2B1          More BioActivity Data..
Tested Compound:
Description:
Title: Functional characterization of pH-sensitive organic anion transporting polypeptide OATP-B in human.

Abstract: The pH-sensitive activity of human organic anion transporting polypeptide OATP-B, which is expressed at the apical membrane of human small intestinal epithelial cells, was functionally characterized. When initial uptake of estrone-3-sulfate, a typical substrate of OATP, was studied kinetically, we observed an increase in V(max) with decrease of pH from 7.4 to 5.0, whereas the change in K(m) was negligible. OATP-B-mediated uptake of estrone-3-sulfate was independent of sodium, chloride, bicarbonate, or glutathione, whereas the proton ionophore carbonylcyanide p-trifluoromethoxyphenylhydrazone exhibited a pH-dependent inhibitory effect, suggesting that a proton gradient is a driving force for OATP-B. When OATP-B was expressed in human embryonic kidney 293 cells, uptake activities for anionic compounds showed various kinds of pH sensitivity. Dehydroepiandrosterone-sulfate, estrone-3-sulfate, and fexofenadine were transported by OATP-B at both neutral and acidic pH, whereas estradiol-17beta-glucuronide, acetic acid, and lactic acid were not transported at all. Transport of taurocholic acid and pravastatin by OATP-B was observed only at acidic pH, demonstrating a pH-sensitive substrate specificity of OATP-B. Because the physiological pH close to the surface of intestinal epithelial cells is acidic, the roles of OATP-B in the small intestine might be different from those in other tissues, such as liver basolateral membrane. Although the driving force for OATP-B has not been fully established, the clarification of factors, such as pH, that affect the OATP-B-activity is essential for an understanding of the physiological and pharmacological relevance of the transporter in the small intestine.
Categorized Comment - additional comments and annotations
From BioAssay Depositor:
Assay Type: Functional
Target Type: Target is a single protein chain
Assay Data Source: TP-search Transporter Database
BAO: Assay Format: cell-based format
Assay Cell Type: HEK293
Assay Test Type: In vitro
Result Definitions
TIDNameDescriptionHistogramTypeUnit
OutcomeThe BioAssay activity outcomeOutcome
1Activity activity commentActivity activity commentString
2Activity standard flagActivity standard flagInteger
3Activity qualifierActivity qualifierString
4Activity published valueActivity published valueFloat
5Activity standard valueActivity standard valueFloat

Data Table (Concise)
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