Change search
ReferencesLink to record
Permanent link

Direct link
Regulation of NAD- and NADP-dependent isocitrate dehydrogenases by reduction levels of pyridine nucleotides in mitochondria and cytosol of pea leaves
Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).ORCID iD: 0000-0001-5900-7395
2003 (English)In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1606, no 1-3, 117-125 p.Article in journal (Refereed) Published
Abstract [en]

Regulation of NAD- and NADP-dependent isocitrate dehydrogenases (NAD-ICDH, EC, and NADP-ICDH, EC by the level of reduced and oxidized pyridine nucleotides has been investigated in pea (Pisum sativum L.) leaves. The affinities of mitochondrial and cytosolic ICDH enzymes to substrates and inhibitors were determined on partially purified preparations in forward and reverse directions. From the kinetic data, it follows that NADP(+)- and NAD+-dependent isocitrate dehydrogenases in mitochondria represent a system strongly responding to the intramitochondrial NADPH and NADH levels. The NADPH, NADP(+), NADH and NAD(+) concentrations were determined by subcellular fractionation of pea leaf protoplasts using membrane filtration in mitochondria and cytosol in darkness and in the light under saturating and limiting CO2 Conditions. The cytosolic NADPH/NADP ratio was about I and almost constant both in darkness and in the light. In mitochondria, the NADPH/NADP ratio was low in darkness (0.2) and increased in the light, reaching 3 in limiting CO2 conditions compared to I in saturating CO2. At high reduction levels of NADP and NAD observed at limiting CO2 in the light, i.e. when photorespiratory glycine is the main mitochondrial substrate, isocitrate oxidation in mitochondria will be suppressed and citrate will be transported to the cytosol ('citrate valve'), where the cytosolic NADP-ICDH supplies 2-oxoglutarate for the photorespiratory ammonia refixation. (C) 2003 Elsevier B.V. All rights reserved.

Place, publisher, year, edition, pages
2003. Vol. 1606, no 1-3, 117-125 p.
Keyword [en]
ammonia refixation, citrate valve, isocitrate dehydrogenase, NAD(P)H/NAD(P) ratio, photorespiration, plant mitochondria
URN: urn:nbn:se:umu:diva-44651DOI: 10.1016/S0005-2728(03)00106-3ISI: 000185593100009OAI: diva2:434123
Available from: 2011-08-12 Created: 2011-06-09 Last updated: 2015-04-29

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Gardeström, Per
By organisation
Department of Plant PhysiologyUmeå Plant Science Centre (UPSC)
In the same journal
Biochimica et Biophysica Acta - Bioenergetics

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 18 hits
ReferencesLink to record
Permanent link

Direct link