Journal Article

A plasma membrane‐enriched fraction isolated from the coats of developing pea seeds contains H<sup>+</sup>‐symporters for amino acids and sucrose

A. de Jong and A.C. Borstlap

in Journal of Experimental Botany

Published on behalf of Society for Experimental Biology

Volume 51, issue 351, pages 1671-1677
Published in print October 2000 | ISSN: 0022-0957
Published online October 2000 | e-ISSN: 1460-2431 | DOI: http://dx.doi.org/10.1093/jexbot/51.351.1671
A plasma membrane‐enriched fraction isolated from the coats of developing pea seeds contains H+‐symporters for amino acids and sucrose

Show Summary Details

Preview

Aqueous polymer two‐phase partitioning was used to obtain a plasma membrane‐enriched fraction from coats of developing pea (Pisum sativum L.) seeds in the filling stage. Uptake of amino acids and sucrose by vesicles from this fraction was determined after imposition of gradients of proton concentration (ΔpH, inside alkaline) and electrical potential (Δψ, inside negative) across the vesicle membrane. The uptake of sucrose and the amino acids l‐valine, l‐lysine, and l‐glutamic acid was stimulated by the imposition of ΔpH. The imposition of Δψ, either in the presence or in the absence of ΔpH, stimulated the uptake of l‐valine and l‐lysine, but had no detectable effect on the uptake of sucrose and l‐glutamic acid. The proton‐motive‐force‐driven uptake of all four substrates was abolished by the protonophore carbonylcyanide m‐chlorophenyl‐hydrazone (CCCP). The results demonstrate the presence of H+‐symporters for sucrose and amino acids in pea seed coats. This is running counter to the previously reported finding that their uptake by isolated pea seed coats was insensitive to CCCP, and that the uptake of sucrose, l‐valine, and l‐glutamic acid displayed linear kinetics. Possible causes of this discrepancy will be discussed.

Keywords: Amino acids; plasma membrane; proton symport; seed coat; sucrose.

Journal Article.  4218 words.  Illustrated.

Subjects: Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.