Transport and recognition of aminopeptidase-resistant cellobiose-coupled tyrosylglycylglycine by intestinal Na+/glucose cotransporter (SGLT1): Recognition of sugar conjugates by SGLT1 is much less restricted than transport

Transport and recognition of aminopeptidase-resistant cellobiose-coupled ty rosylglycylglycine (CcpTGG) by intestinal Na+/glucose cotransporter (SGLT1) was examined in rat small intestine. Inhibitory effect of phloridzin (SGLT 1 inhibitor) on the CcpTGG transport was extremely low: Concentration depen dence of the CcpTGG transport was observed, but the primary component of tr ansport was passive diffusion. However, CcpTGG significantly inhibited SGLT 1-mediated transport, indicating its recognition by SGLT1. Other glucose-co njugates also inhibited SGLT1-mediated transport. These results indicate th at recognition of sugar conjugates by SGLT1 is much less restricted than tr ansport, and that it should be relatively easier to design SGLT1 inhibitors than SGLT1-transportable sugar conjugates.