Photosynthetica

, Volume 38, Issue 3, pp 415–419

Phosphoenolpyruvate Carboxylase Purified from Leaves of C3, C4, and C3-C4 intermediate species of Alternanthera: Properties at Limiting and Saturating Bicarbonate

Authors

  • Bhaskarrao Chinthapalli
    • Department of Plant Sciences, School of Life SciencesUniversity of Hyderabad
  • Chitra Raghavan
    • Department of Plant Sciences, School of Life SciencesUniversity of Hyderabad
  • O. Bläsing
    • Institut für Entwicklungs- und Molekularbiologie der PflanzenHeinrich-Heine-Universität
  • P. Westhoff
    • Institut für Entwicklungs- und Molekularbiologie der PflanzenHeinrich-Heine-Universität
  • A.S. Raghavendra
    • Department of Plant Sciences, School of Life SciencesUniversity of Hyderabad
Article

DOI: 10.1023/A:1010981807667

Cite this article as:
Chinthapalli, B., Raghavan, C., Bläsing, O. et al. Photosynthetica (2001) 38: 415. doi:10.1023/A:1010981807667

Abstract

Phosphoenolpyruvate carboxylase (PEPC) was purified from leaves of four species of Alternanthera differing in their photosynthetic carbon metabolism: Alternanthera sessilis (C3), A. pungens (C4), A. ficoides and A. tenella (C3-C4 intermediates or C3-C4). The activity and properties of PEPC were examined at limiting (0.05 mM) or saturating (10 mM) bicarbonate concentrations. The Vmax as well as Km values (for Mg2+ or PEP) of PEPC from A. ficoides and A. tenella (C3-C4 intermediates) were in between those of C3 (A. sessilis) and C4 species (A. pungens). Similarly, the sensitivity of PEPC to malate (an inhibitor) or G-6-P (an activator) of A. ficoides and A. tenella (C3-C4) was also of intermediate status between those of C3 and C4 species of A. sessilis and A. pungens, respectively. In all the four species, the maximal activity (Vmax), affinity for PEP (Km), and the sensitivity to malate (KI) or G-6-P (KA) of PEPC were higher at 10 mM bicarbonate than at 0.05 mM bicarbonate. Again, the sensitivity to bicarbonate of PEPC from C3-C4 intermediates was in between those of C3- and C4-species. Thus the characteristics of PEPC of C3-C4 intermediate species of Alternanthera are intermediate between C3- and C4-type, in both their kinetic and regulatory properties. Bicarbonate could be an important modulator of PEPC, particularly in C4 plants.

glucose-6-phosphatemalateproteinsspecies differences in enzyme activity

Copyright information

© Kluwer Academic Publishers 2001