Plant Physiol. email content delivery
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Plant Physiology 87:64-68 (1988)
© 1988 American Society of Plant Biologists

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Web of Science (11)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Neuhaus, H. E.
Right arrow Articles by Latzko, E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Neuhaus, H. E.
Right arrow Articles by Latzko, E.
Agricola
Right arrow Articles by Neuhaus, H. E.
Right arrow Articles by Latzko, E.
Metabolism and Enzymology

Transport of Phosphoenolpyruvate by Chloroplasts from Mesembryanthemum crystallinum L. Exhibiting Crassulacean Acid Metabolism 1

H. Ekkehard Neuhaus, Joseph A. M. Holtum2 and Erwin Latzko

Botanisches Institut, Westfälische Wilhelms Universität, Schlo{beta}garten 3, 4400 Münster, Federal Republic of Germany

Chloroplasts from CAM-Mesembryanthemum crystallinum can transport phosphoenolpyruvate (PEP) across the envelope. The initial velocities of PEP uptake in the dark at 4°C exhibited saturation kinetics with increasing external PEP concentration. PEP uptake had a Vmax of 6.46 (±0.05) micromoles per milligram chlorophyll per hour and an apparent KmPEP of 0.148 (±0.004) millimolar. The uptake was competitively inhibited by Pi (apparent Ki = 0.19 millimolar), by glycerate 3-phosphate (apparent Ki = 0.13 millimolar), and by dihydroxyacetone phosphate, but malate and pyruvate were without effect. The chloroplasts were able to synthesize PEP when presented with pyruvate. PEP synthesis was light dependent. The prolonged synthesis and export of PEP from the chloroplasts required the presence of Pi or glycerate 3-phosphate in the external medium. It is suggested that the transport of pyruvate and PEP across the chloroplasts envelope is required during the gluconeogenic conversion of carbon from malate to storage carbohydrate in the light.

2 Present address: Waite Agricultural Research Institute, P. O. Box 1, Glen Osmond 5064, South Australia, Australia.

1 Dedication: This manuscript is dedicated to Prof. P. F. Brownell on the eve of his retirement.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ASPB Publications PLANT PHYSIOLOGY® THE PLANT CELL
Copyright © 1988 by the American Society of Plant Biologists