Skip to main content
padlock icon - secure page this page is secure

Free Content Regulation of Rubisco activation in antisense plants of tobacco containing reduced levels of Rubisco activase

Download Article:

The full text article is temporarily unavailable.

We apologise for the inconvenience. Please try again later.


Following an increase in photon flux density (PFD), ribulose bisphosphate carboxylase/oxygenase (Rubisco) undergoes a slow activation which substantially limits the rate of photosynthesis. This activation process is mediated in part by Rubisco activase. Antisense DNA plants of tobacco were used to quantify the degree to which activase limits Rubisco activation. Reductions in leaf activase content caused proportional reductions in the rate of Rubisco activation following a PFD increase from 110 to 1200 mumol m-2 sec-1. This was the case for activase levels up to and slightly beyond normal wild-type activase levels. Activase therefore has a flux control coefficient of unity with respect to the Rubisco activation flux. Such a high control coefficient has rarely been measured for any metabolic system, and this is the highest control coefficient measured for an important photosynthetic flux. In contrast, the rate of Rubisco inactivation in leaves following a drop in PFD of 1200 to 110 mumol m-2 sec-1 was unchanged by a 60% reduction in activase levels. Despite the high degree of control that activase exerts over the rate of activation, and thus non-steady-state photosynthesis, it was shown that steady-state photosynthesis was largely unaffected by activase concentration until it was reduced below approximately 15% of the wild-type level. The significance of these results and their implications for published models of Rubisco activation are discussed.
No References
No Citations
No Supplementary Data
No Article Media
No Metrics

Document Type: Research Article

Affiliations: 1: School of Botany, The University of Melbourne, Parkville, Victoria 3052, Australia 2: School of Biological Sciences, Australian National University, Canberra, ACT 2601, Australia, 3: Department of Biology, Utah State University, Logan, Utah, USA

Publication date: April 1, 1998

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more