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Linear relationship of phlorizin‐binding capacity and hexose uptake during differentiation in a clone of LLC‐PK 1 cells
Author(s) -
Amsler Kurt,
Cook John S.
Publication year - 1985
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041220214
Subject(s) - phlorizin , hexose , clone (java method) , transporter , population , biochemistry , chemistry , binding site , efflux , membrane transport , biology , glucose transporter , membrane , endocrinology , enzyme , gene , demography , sociology , insulin
With a clone of (Cl 4) of LLC‐PK cells, which develop a high capacity for Na + ‐dependent hexose uptake over time (days) in culture, we show that increasing uptake capacity is paralleled by an increase in the number of phlorizin‐binding sites in the population. The linear relationship between binding and hexose transport is the same whether the cells differentiate spontaneously or are induced by either methylisobutylxanthine or hexamethylene bisacet‐amide. The constancy of the relationship suggests that the primary factor in transport development is the number of transporters in the cells rather than other possible factors like a change in membrane potential or decreased efflux. The K d for phlorizin binding is .08 ± .04 μM, and corresponds to K i of 0.10 μM for transport inhibition. The turnover number of the transporter is estimated to be 170 ± 40 molecules per second of α‐methyl glucoside.