Two phosphoenolpyruvate carboxykinases coexist in the Crassulacean Acid Metabolism plant Ananas comosus. Isolation and characterization of the smaller 65 kDa form

Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Bibliographische Detailangaben
Veröffentlicht in:Plant physiology and biochemistry : PPB. - 1991. - 49(2011), 6 vom: 01. Juni, Seite 646-53
1. Verfasser: Martín, Mariana (VerfasserIn)
Weitere Verfasser: Rius, Sebastián Pablo, Podestá, Florencio Esteban
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2011
Zugriff auf das übergeordnete Werk:Plant physiology and biochemistry : PPB
Schlagworte:Journal Article Research Support, Non-U.S. Gov't Plant Proteins Protein Isoforms Oxaloacetic Acid 2F399MM81J Phosphoenolpyruvate 73-89-2 Phosphoenolpyruvate Carboxylase EC 4.1.1.31
Beschreibung
Zusammenfassung:Copyright © 2011 Elsevier Masson SAS. All rights reserved.
Two phosphoenolpyruvate carboxykinase (PEPCK, EC 4.1.1.49) isoforms of 74 and 65 kDa were found to coexist in vivo in pineapple leaves, a constitutive Crassulacean Acid Metabolism plant. The 65 kDa form was not the result of proteolytic cleavage of the larger form since extraction methods reported to prevent PEPCK proteolysis in other plant tissues failed to yield a single immunoreactive PEPCK polypeptide in leaf extracts. In this work, the smaller form of 65 kDa was purified to homogeneity and physically and kinetically characterized and showed parameters compatible with a fully active enzyme. The specific activity was nearly twice higher for decarboxylation of oxaloacetate when compared to carboxylation of phosphoenolpyruvate. Kinetic parameters fell within the range of those estimated for other plant PEPCKs. Its activity was affected by several metabolites, as shown by inhibition by 3-phosphoglycerate, citrate, malate, fructose-1,6-bisphosphate, l-asparagine and activation of the decarboxylating activity by succinate. A break in the Arrhenius plot at about 30°C indicates that PEPCK structure is responsive to changes in temperature. The results indicate that pineapple leaves contain two PEPCK forms. The biochemical characterization of the smaller isoform performed in this work suggests that it could participate in both carbon and nitrogen metabolism in vivo by acting as a decarboxylase
Beschreibung:Date Completed 06.12.2011
Date Revised 30.09.2020
published: Print-Electronic
Citation Status MEDLINE
ISSN:1873-2690
DOI:10.1016/j.plaphy.2011.02.015