Affinity labelling of the folate-binding protein in pig intestine.

摘要: A specific transport system for folate and a high-affinity folate-binding protein have been identified in pig intestinal brush-border membranes. To determine if the binding plays role folic acid (PteGlu) uptake to cell, inactivation of by N-hydroxysuccinimide esters (NHS-PteGlu) was compared. In addition, number proteins modified affinity reagent assessed. Brush-border vesicles were incubated with various concentrations NHS-PteGlu or NHS-methotrexate. Transport [3H]PteGlu measured at 37 4 degrees C respectively using vacuum-filtration technique. NHS-methotrexate specifically inhibited PteGlu transport. Incubating 1 microM-NHS-PteGlu inactivated 60% 80%. Half-maximal inhibition both observed similar (0.05 0.07 respectively). Treating radiolabelled followed gel electrophoresis autoradiography revealed labelled an Mr 56,000. These results indicate that are identical function is into cell.