Proline transport by brush-border membrane vesicles of lobster antennal glands

摘要: Purified brush-border membrane vesicles (BBMV) of lobster antennal gland labyrinth and bladder were separately formed by a magnesium precipitation technique. L-[3H]proline uptake was stimulated transmembrane NaCl gradient [outside (o) greater than inside (i)] to extent in BBMV from those the bladder. Detailed study proline-transport processes revealed specific dependence on NaCl, with negligible stimulatory effects NaSCN, Na-gluconate, or KCl. A proton (o i) without effect proline transport. potential difference alone, presence equilibrated L-[3H]proline, led net influx labeled amino acid, suggesting that process electrogenic capable bringing about transfer positive charge vesicle interior. Although Na Cl able bring alone under Na- L-[3H]proline-equilibrated conditions not, only could energize carrier through cotransport, while anion served an essential activating role. Proline these occurred combination at least one saturable Michaelis-Menten system (apparent Kt = 0.37 mM; apparent JM 1.19 nmol.mg protein-1.10 s-1) diffusion (P 0.33 s-1.mM-1). Static head analysis transport suggested cotransport stoichiometry 2 Na:1 activation ion.