Transport of glycyl-l-proline by human intestinal brush border membrane vesicles

摘要: This study characterizes the transport of [1-14C]glycyl-L-proline into purified brush border membrane vesicles prepared from human small intestine. Time-course uptake curves glycyl-L-proline were similar under sodium thiocyanate or potassium gradient conditions (extravesicular greater than intravesicular) and did not show any overshoot phenomena. The glycine proline, however, was stimulated by presence gradient. Measurement peptide with increasing medium osmolarity showed that transported an osmotically reactive intravesicular space insignificant binding to surface vesicles. Only 2% in incubation media hydrolyzed after 10 min incubation. Also, there no hydrolysis space. effects concentrations on saturable conformed Michaelis-Menten kinetics a Km 4.1 +/- 0.5 mM Vmax 1.53 0.07 nmol/mg protein X min. Free amino acids inhibit while dipeptides tripeptides exerted appreciable inhibition (up 60%). Our results intestinal as intact carrier-mediated, Na+-independent process.