Mechanism of L-lysine transport by pea protoplasts

Abstract

L - Lysine uptake was studied in pea protoplasts to characterize the transport process. The uptake was pH dependent with optimum at pH 5.8. A kinetic analysis of uptake showed that L- lyslne uptake was biphasic. The respiratory inhibitors, sodium arsenate, azide, iodoacetate and 2, 4, dinitrophenol, inhibited the uptake of L- lysine at a final concentration of 0.1 mol m ^-3 suggesting it to be mediated in part by an active process. Competitive inhibition of L- lysine uptake by only L - arglnine and of L- leucine and glycine uptake by several amino acids indicated that L- lysine uptake occurs via a specific system whereas the uptake of L- leucine and glycine was mediated through a relatively non - specific permease.