Effect of High Physiological Temperatures on NAD+ Content of Green Leaf Mitochondria (Apparent Inhibition of Glycine Oxidation).
AUTOR(ES)
Lenne, C.
RESUMO
We observed a rapid decline in the rate of glycine oxidation by purified pea (Pisum sativum L.) leaf mitochondria preincubated at 40[deg]C for 2 min. In contrast, exogenous NADH and succinate oxidations were not affected by the heat treatment. We first demonstrated that the inhibition of glycine oxidation was not attributable to a direct effect of high temperatures on glycine decarboxylase/serine hydroxymethyltransferase. We observed that (a) addition of NAD+ to the incubation medium resulted in a resumption of glycine-dependent O2 uptake by intact mitochondria, (b) addition of NAD+ to the suspending medium prevented the decline in the rate of glycine-dependent O2 consumption by pea leaf mitochondria incubated at 40[deg]C, (c) NAD+ concentration in the matrix space collapses within only 5 min of warm temperature treatment, and (d) mitochondria treated with the NAD+ analog N-4-azido-2-nitrophenyl-4-aminobutyryl-3[prime]-NAD+ retained high rates of glycine-dependent O2 uptake after preincubation at 40[deg]C. Therefore, we conclude that the massive and rapid efflux of NAD+, leading to the apparent inhibition of glycine oxidation, occurs through the specific NAD+ carrier present in the inner membrane of plant mitochondria. Finally, our data provide further evidence that NAD+ is not firmly bound to the inner membrane.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=158900Documentos Relacionados
- Effect of NAD+ on Malate Oxidation in Intact Plant Mitochondria 1
- Role of Glutamate-oxaloacetate Transaminase and Malate Dehydrogenase in the Regeneration of NAD+ for Glycine Oxidation by Spinach leaf Mitochondria 1
- Macromolecular enzymatic product of NAD+ in liver mitochondria.
- Helminthosporium maydis Race T Toxin Induces Leakage of NAD+ from T Cytoplasm Corn Mitochondria 1
- Photoaffinity labeling of ATP and NAD+ binding sites on recombinant human interleukin 2.