Planta

, Volume 152, Issue 4, pp 307–313

The compartmentation of carboxylating and decarboxylating enzymes in guard cell protoplasts

  • H. Schnabl
Article

DOI: 10.1007/BF00388254

Cite this article as:
Schnabl, H. Planta (1981) 152: 307. doi:10.1007/BF00388254

Abstract

Guard cell and mesophyll cell protoplasts of Vicia faba L. were purified and separated into cytoplasmic and plastid fractions by a selective silicone-oil filtration. Before fractionation, the protoplasts were ruptured by a low speed centrifugation through a narrow-aperture nylon net placed in a plastic vial. This protoplast homogenation and subsequently the silicone-oil fractionation offer the possibility of investigating the comparatmentation of the enzymatic carboxylating (ribulose bisphosphate carboxylase EC 4.1.1.39, phosphoenolpyruvate carboxylase EC 4.1.1.31, NAD+ and NADP+ linked malate dehydrogenase EC 1.1.1.37) and decarboxylating pathways of malic (malic enzyme EC 1.1.1.40, phosphoenolpyruvate carboxykinase EC 4.1.1.32, pyruvate orthophosphate dikinase EC 2.7.9.1) which occur during the swelling and shrinking of the guard cell protoplasts. A model is proposed which describes the transport processes of malic acid during the starch-malate balance as correlated to the volume changes of the protoplasts. As the enzymes and their compartmentation in the guard cell protoplasts seem to be consistent with those of crassulacean acid metabolism (CAM) plants, the metabolism of stomata and of CAM cells is compared.

Key words

Carboxylases Decarboxylases Guard cell protoplast Malic acid Protoplast fractionation Vicia 

Abbreviations

AQ

anthraquinone-2-sulfonic acid

CAM

Crassulacean acid metabolism

DCPIPred

2,6-dichlorophenol-indophenol

DTT

dithiothreitol

EDTA

ethylendiamine tetraacetic acid

GAPDH

glyceraldehyde-3-phosphate dehydrogenase

HEPES

N-2-hydroxyethyl-piperazine-N-2-ethane sulphonic acid

MDH

malante dehydrogenase

MES

2(N-morpholino) ethane sulphonic acid

OAA

oxaloacetic acid

PEP

phosphoenolpyruvate

PSI

photosystem I

KuP2

ribulose bisphosphate

Copyright information

© Springer-Verlag 1981

Authors and Affiliations

  • H. Schnabl
    • 1
  1. 1.Institut für Botanik und MikrobiologieTechnische Universität MünchenMünchen 2Federal Republic of Germany

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