Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow E-letters: Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when E-letters are posted
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 Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by MORRELL, S.
Right arrow Articles by DAVIES, D. D.
Right arrow Search for Related Content
PubMed
Right arrow Articles by MORRELL, S.
Right arrow Articles by DAVIES, D. D.
Agricola
Right arrow Articles by MORRELL, S.
Right arrow Articles by DAVIES, D. D.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 1990 Oxford University Press

RESEARCH-ARTICLE

Regulation of Pyruvate Decarboxylase In Vitro and In Vivo

S. MORRELL1,3,4, H. GREENWAY1 and D. D. DAVIES2

1Crop and Pasture Science, School of Agriculture, University of Western Australia Nedlands, W.A. 6009, Australia
2School of Biological Sciences, University of East Anglia Norwich, NR4 7TJ, UK
3Department of Biochemistry and Physiology, Rothamsted Experimental Station Harpenden, Herts HL5 250, UK

4 To whom correspondence should be addressed.

Results presented in this paper strongly support the view that regulation of the key enzyme of alcoholic fermentation, pyruvate decarboxylase (PDC), is achieved in a number of ways, all associated with possible lowering of the cytoplasmic pH during anoxia. These mechanisms include not only the well-known acid pH optimum of PDC, but also long-term, reversible changes in characteristics of the enzyme established both in vitro and in vivo.

Following transfer of desalted extracts from pH 6.0 to 7.4, maximal activity of PDC was decreased, while there was a considerable increase in the lag before maximal activity was reached. Similar changes in enzyme characteristics were observed when wheat (Triticum aestivum L. cv. Gamenya) roots and rice (Oryza sativa L. cv. Calrose) coleoptiles were transferred from anoxic to aerobic solutions, provided PDC was assayed within 10 min of the start of maceration. All of the above changes were usually readily reversible when extracts were returned to pH 6.0, or when plants were returned to anoxic solutions.

Additional regulation of PDC would be achieved by the S0.5 for pyruvate which is 0.75 mol m–3 at pH 6.0, 1.0 mol m–3 at pH 6.8, and 2.5 mol m–3 at pH 7.4; the latter is well above estimates for pyruvate concentrations in the cytoplasm of aerated tissues.

We assess that the combined effects of the acid pH optimum, the high S0.5 at pH 7.4 and the long-term decreases in activity observed during incubation at pH 7.4 would reduce PDC activity in aerobic cells to at most 7% of the activity in anoxic cells. Possible additional controls for the pathway of alcoholic fermentation are briefly considered.

Key words: PDC, regulation, anoxia


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 Plant Physiol.Home page
K. P. Ismond, R. Dolferus, M. De Pauw, E. S. Dennis, and A. G. Good
Enhanced Low Oxygen Survival in Arabidopsis through Increased Metabolic Flux in the Fermentative Pathway
Plant Physiology, July 1, 2003; 132(3): 1292 - 1302.
[Abstract] [Full Text] [PDF]

Home page
 ANN BOT (LOND)Home page
B. MOHANTY and B.-L. ONG
Contrasting Effects of Submergence in Light and Dark on Pyruvate Decarboxylase Activity in Roots of Rice Lines Differing in Submergence Tolerance
Ann. Bot., January 2, 2003; 91(2): 291 - 300.
[Abstract] [Full Text] [PDF]

Home page
 ANN BOT (LOND)Home page
A. RAWYLER, S. ARPAGAUS, and R. BRAENDLE
Impact of Oxygen Stress and Energy Availability on Membrane Stability of Plant Cells
Ann. Bot., October 1, 2002; 90(4): 499 - 507.
[Abstract] [Full Text] [PDF]

Home page
 J Exp BotHome page
J. Gibbs, S. Morrell, A Valdez, T.L Setter, and H. Greenway
Regulation of alcoholic fermentation in coleoptiles of two rice cultivars differing in tolerance to anoxia
J. Exp. Bot., April 1, 2000; 51(345): 785 - 796.
[Abstract] [Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.