2.A.60.1.20
Solute carrier organic anion transporter family member 2B1 (Organic anion transporter B) (OATP-B, OAT2B1, OAT2B1 or OATP2B1) (Organic anion transporter polypeptide-related protein 2) (OATP-RP2) (OATPRP2) (Solute carrier family 21 member 9).  Catalyzes anion exchange in the placenta with cytoplasmic glutamate as the probable exchanging anion (Lofthouse et al. 2015) as well as uptake of ochratoxin (OTA) (Qi et al. 2017).  A trp residue in the middle of TMS11 is essential (Bian et al. 2016). TMSs 1, 2, 4 and 5 seem to form the substrate binding pocket, and TMS 1 is also essential for stability (Fang et al. 2018). The inhibitory effects of the main soy isoflavones (daidzin, daidzein, genistin, genistein, glycitin, glycitein, biochanin A, formononetin) and their metabolites formed in vivo (S-equol, O-desmethylangolensin) towards the human OATP2B1 transporter have been characterized (Navrátilová et al. 2018). Aglycones of soy isoflavones and the main biologically active metabolite S-equol were able to inhibit hOATP2B1-mediated transport with Ki values for most aglycones ranging from 1 to 20 muM (Navrátilová et al. 2018). An interaction between hyperforin and OATP2B1 contributes to hepatocellular and intestinal absorption of its substrates (Schäfer et al. 2019). Human (h) and rat (r) don't have the same characteristics.  hOATP2B1, but not rOATP2B1, is involved in intestinal absorption. While bromosulfophthalein and atorvastatin were substrates of both transporters, the steroid sulfate conjugates estrone 3-sulfate (E1S), progesterone sulfate and dehydroepiandrosterone sulfate were only transported by hOATP2B1 (Hussner et al. 2021). SN-38 is absorbed into the enterocytes via OATP2B1, glucuronidated by UGTs to SN-38G, and excreted into the digestive tract lumen by MRP2 and BCRP. SN-38G can be deconjugated by β-glucuronidase from intestinal bacteria in the digestive tract lumen to regenerate SN-38 (Martha et al. 2023). Interplay of OATP1A/1B/2B1 uptake transporters and ABCB1 and ABCG2 efflux transporters are important in the handling of bilirubin and drugs (Li et al. 2024).