title: Proline transport into brush border membrane vesicles from the midgut of Manduca sexta larvae.
abstract: The unidirectional transport of proline by midgut epithelium cells of the tobacco hornworm, Manduca sexta, was investigated in brush border membrane vesicles. Both K.(+)-stimulated and K(+)-insensitive transport pathways were identified. Analyses of K(+)-dependent proline transport revealed 1:1 ratio of K+ to proline, a Km of 13 mM for K+ and a decrease in both Km (from 18 mM to 3 mM) and Vmax (from 37 nmol/mg protein/min to 10 nmol/mg protein/min) for proline in the presence of a K+ gradient. The profiles of cis-inhibition by other amino acids demonstrated that proline is transported into midgut cells by a transport system that is shared by other neutral amino acids.
authors.affiliation: Department of Entomology, Purdue University, West Lafayette, IN 47907-1158.
authors.forename: M
authors.initials: M
authors.lastname: Reuveni
authors.forename: P E
authors.initials: PE
authors.lastname: Dunn
mesh_terms: D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D004064:Digestive System / Q000378:metabolism; D007700:Kinetics; D007814:Larva / Q000378:metabolism; D008871:Microvilli / Q000378:metabolism; D009036:Moths / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D011392:Proline / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D011392:Proline; D011188:Potassium