Regulation of Pea Mitochondrial Pyruvate Dehydrogenase Complex 1: Does Photorespiratory Ammonium Influence Mitochondrial Carbon Metabolism?
AUTOR(ES)
Schuller, Kathryn A.
RESUMO
Inactivation of the pyruvate dehydrogenase complex catalyzed by pyruvate dehydrogenase kinase was studied using intact mitochondria purified from green leaf tissue of pea (Pisum sativum L.) and dialyzed mitochondrial extracts. Thiamine pyrophosphate was inhibitory in dialyzed extracts but not in intact mitochondria, except in the presence of high concentrations of Na+. NH4+, at concentrations as low as 20 micromolar, markedly stimulated inactivation in dialyzed extracts. K+ in the range 1 to 10 millimolar also enhanced inactivation. In contrast, Na+ was without affect at lower concentrations but was inhibitory at 10 to 100 millimolar levels. The effect of NH4+ is discussed in relation to a possible regulatory interaction between photorespiratory NH4+ production and the entry of carbon into the tricarboxylic acid cycle by way of the pyruvate dehydrogenase complex.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1055997Documentos Relacionados
- Some Kinetic and Regulatory Properties of the Pea Mitochondrial Pyruvate Dehydrogenase Complex 1
- Regulation of Steady State Pyruvate Dehydrogenase Complex Activity in Plant Mitochondria 1: Reactivation Constraints
- Some Properties of Pea Mitochondrial Phospho-Pyruvate Dehydrogenase-Phosphatase 1
- Regulation of Plant Pyruvate Dehydrogenase Complex by Phosphorylation 1
- Pea leaf mitochondrial pyruvate dehydrogenase complex is inactivated in vivo in a light-dependent manner.
