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


     

Plant Physiology 57:623-627 (1976)
© 1976 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 (10)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Givan, C. V.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Givan, C. V.
Agricola
Right arrow Articles by Givan, C. V.
Articles

Glutamine Synthesis and Its Relation to Photophosphorylation in Pisum Chloroplasts

Effects of 3-(3,4-Dichlorophenyl)-1,1-dimethylurea and Antimycin A 1

Curtis V. Givan

a Department of Plant Biology, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, England, United Kingdom

Illuminated pea (Pisum sativum) chloroplasts can convert glutamate to glutamine using ATP generated by photophosphorylation to drive the glutamine-synthetase reaction. Light-dependent glutamine synthesis is sensitive to 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU), but only at concentrations higher than are necessary to suppress photoreduction of ferricyanide or phosphoglycerate. Conversely, glutamine synthesis is far more sensitive to antimycin A than is photoconversion of phosphoglycerate to triosephosphate. When 3.8 mM phosphoglycerate is supplied, glutamine synthesis is stimulated in both the presence and absence of antimycin A.

These data seem to be consistent with the operation of an endogenous, DCMU-sensitive, phosphorylation process-possibly cyclic-which can support glutamine synthesis in white light under aerobic conditions. The stimulatory effect of phosphoglycerate suggests that noncyclic phosphorylation is initiated or accelerated when this substrate is supplied. This noncyclic process evidently provides ATP over and above the amount required for phosphoglycerate photoreduction, i.e. the ATP/e2 ratio exceeds 1.0. The additional ATP produced under these conditions is available for glutamine synthesis and lessens its dependence on cyclically (or pseudocyclically) generated ATP.

1 This paper is dedicated to Lawrence R. Blinks, Professor Emeritus of Plant Physiology at Stanford University, on the occasion of his 75th birthday.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ASPB Publications PLANT PHYSIOLOGY® THE PLANT CELL
Copyright © 1976 by the American Society of Plant Biologists