Planta

, Volume 181, Issue 1, pp 97–103

Regulation of sedoheptulose-1,7-bisphosphatase by sedoheptulose-7-phosphate and glycerate, and of fructose-1,6-bisphosphatase by glycerate in spinach chloroplasts

  • Dieter Schimkat
  • Dieter Heineke
  • Hans W. Heldt
Article

DOI: 10.1007/BF00202330

Cite this article as:
Schimkat, D., Heineke, D. & Heldt, H.W. Planta (1990) 181: 97. doi:10.1007/BF00202330

Abstract

Using partially purified sedoheptulose-1,7-bisphosphatase from spinach (Spinacia oleracea L.) chloroplasts the effects of metabolites on the dithiothreitoland Mg2+-activated enzyme were investigated. A screening of most of the intermediates of the Calvin cycle and the photorespiratory pathway showed that physiological concentrations of sedoheptulose-7-phosphate and glycerate specifically inhibited the enzyme by decreasing its maximal velocity. An inhibition by ribulose-1,5-bisphosphate was also found. The inhibitory effect of sedoheptulose-7-phosphate on the enzyme is discussed in terms of allowing a control of sedoheptulose-1,7-bisphosphate hydrolysis by the demand of the product of this reaction. Subsequent studies with partially purified fructose-1,6-bisphosphatase from spinach chloroplasts showed that glycerate also inhibited this enzyme. With isolated chloroplasts, glycerate was found to inhibit CO2 fixation by blocking the stromal fructose-1,6-bisphosphatase. It is therefore possible that the inhibition of the two phosphatases by glycerate is an important regulatory factor for adjusting the activity of the Calvin cycle to the ATP supply by the light reaction.

Key words

Carbon dioxide fixation Fructose-1,6-bisphosphatase Glycerate Photosynthesis (enzyme regulation) Sedoheptulose-1,7-bisphosphatase Sedoheptulose-7-phosphate Spinacia (chloroplasts) 

Abbreviations

DTT

dithiothreitol

FBPase

fructose-1,6-bisphosphatase

Fru-1,6-P2

fructose-1,6-bisphosphate

Fru-6-P

fructose-6-phosphate

3-PGA

3-phosphoglycerate

Ru-1,5-P2

ribulose-1,5-bisphosphate

Ru-5-P

ribulose-5-phosphate

SBPase

sedoheptulose-1,7-bisphosphatase

Sed-1,7-P2

sedoheptulose-1,7-bisphosphate

Sed-7-P

sedoheptulose-7-phosphate

Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • Dieter Schimkat
    • 1
  • Dieter Heineke
    • 1
  • Hans W. Heldt
    • 1
  1. 1.Institut für Biochemie der Pflanze, Universität GöttingenGöttingenGermany