The Accumulation of Copper by Microvillar Vesicles Isolated from Human Placenta

Copper uptake from copper-dihistidine complexes by microvillar vesicles from human placenta was studied. Uptake occurred in two phases: a rapid initial binding followed by approximately linear uptake to equilibrium at -5 min. The uptake showed temperature dependence, was saturable (apparent V max 10.5±1.6 nmol/(mg protein.4 min), apparent K m of 0.6±0.12 μmol/L) and decreased with increasing osmotic pressure, showing that the Cu uptake arose from accumulation within the vesicles