THE REDOX LEVELS AND SUBCELLULAR-DISTRIBUTION OF PYRIDINE-NUCLEOTIDES IN ILLUMINATED BARLEY LEAF PROTOPLASTS STUDIED BY RAPID FRACTIONATION
1993 (English)In: Physiologia Plantarum: An International Journal for Plant Biology, ISSN 0031-9317, E-ISSN 1399-3054, Vol. 88, no 1, 10-18 p.Article in journal (Refereed) Published
The redox level and compartmentation of pyridine nucleotides was studied under photorespiratory and non-photorespiratory conditions using rapid fractionation of barley (Hordeum vulgare L. cv. Gunilla, Svalov) leaf protoplasts. From comparative measurements of the NADPH/NADP+ ratio and the ATP/ADP ratio one acidic and one alkaline extraction medium was chosen which quenched the metabolism very efficiently. The mitochondrial NADH/NAD+ was higher under photorespiratory conditions than under non-photorespiratory conditions. Aminoacetonitrile, an inhibitor of the photorespiratory conversion of glycine to serine, lowered the mitochondrial NADH/NAD+ ratio. This supports the hypothesis that glycine oxidation is coupled to oxidative phosphorylation to provide ATP to the cytosol. The chloroplastic NADPH/NADP+ as well as the NADH/NAD+ ratios were quite stable in saturating and limiting CO2 as well as in the presence of aminoacetonitrile, although the triosephosphate/phosphoglycerate ratios changed. Thus, the redox level in the stroma seems to be tightly regulated.
Place, publisher, year, edition, pages
1993. Vol. 88, no 1, 10-18 p.
IdentifiersURN: urn:nbn:se:umu:diva-46912DOI: 10.1111/j.1399-3054.1993.tb01754.xISI: A1993LH31400002OAI: oai:DiVA.org:umu-46912DiVA: diva2:447239