HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 275, Issue 30, 22955-22960, July 28, 2000

This Article Full Text Full Text (PDF) All Versions of this Article: 275/30/22955    most recent M002768200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chen, S. Articles by Halkier, B. A. Search for Related Content PubMed PubMed Citation Articles by Chen, S. Articles by Halkier, B. A. Social Bookmarking                      What's this?

Characterization of Glucosinolate Uptake by Leaf Protoplasts of Brassica napus^*

Sixue Chen and Barbara Ann Halkier

From the Plant Biochemistry Laboratory, Department of Plant Biology, and Center for Molecular Plant Physiology (PlaCe), The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark

The uptake of radiolabeled p-hydroxybenzylglucosinolate (p-OHBG) by protoplasts isolated from leaves of Brassica napus was detected using silicone oil filtration technique. The uptake was pH-dependent with higher uptake rates at acidic pH. Imposition of a pH gradient (internal alkaline) across the plasma membrane resulted in a rapid uptake of p-OHBG, which was inhibited in the presence of carbonyl cyanide m-chlorophenylhydrazone, indicating that the uptake is dependent on a proton motive force. Dissipation of the internal positive membrane potential generated a small influx as compared with that seen for pH gradient (pH). Kinetic studies demonstrated the presence of two uptake systems, a saturable and a linear component. The saturable kinetics indicated carrier-mediated translocation with a K_m of 1.0 mM and a V_max of 28.7 nmol/µl/h. The linear component had very low substrate affinity. The carrier-mediated transport had a temperature coefficient (Q₁₀) of 1.8 ± 0.2 in the temperature range from 4-30 °C. The uptake was against a concentration gradient and was sensitive to protonophores, uncouplers, H⁺-ATPase inhibitors, and the sulfhydryl group modifier p-chloromercuriphenylsulfonic acid. The carrier-mediated uptake system had high specificity for glucosinolates because glucosinolate degradation products, amino acids, sugars, or glutathione conjugates did not compete for p-OHBG uptake. Glucosinolates with different side chains were equally good competitors of p-OHBG uptake, which indicates that the uptake system has low specificity for the glucosinolate side chains. Our data provide the first evidence of an active transport of glucosinolates by a proton-coupled symporter in the plasma membrane of rape leaves.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				M. Zhu, S. Dai, S. McClung, X. Yan, and S. Chen Functional Differentiation of Brassica napus Guard Cells and Mesophyll Cells Revealed by Comparative Proteomics Mol. Cell. Proteomics, April 1, 2009; 8(4): 752 - 766. [Abstract] [Full Text] [PDF]

				A. Raichaudhuri, M. Peng, V. Naponelli, S. Chen, R. Sanchez-Fernandez, H. Gu, J. F. Gregory III, A. D. Hanson, and P. A. Rea Plant Vacuolar ATP-binding Cassette Transporters That Translocate Folates and Antifolates in Vitro and Contribute to Antifolate Tolerance in Vivo J. Biol. Chem., March 27, 2009; 284(13): 8449 - 8460. [Abstract] [Full Text] [PDF]

				Z. Zhai, T. Sooksa-nguan, and O. K. Vatamaniuk Establishing RNA Interference as a Reverse-Genetic Approach for Gene Functional Analysis in Protoplasts Plant Physiology, February 1, 2009; 149(2): 642 - 652. [Abstract] [Full Text] [PDF]

				S. Chen, B. L. Petersen, C. E. Olsen, A. Schulz, and B. A. Halkier Long-Distance Phloem Transport of Glucosinolates in Arabidopsis Plant Physiology, September 1, 2001; 127(1): 194 - 201. [Abstract] [Full Text] [PDF]