|
PLANT PHYSIOLOGY , Vol 114, Issue 4 1413-1419, Copyright © 1997 by American Society of Plant Biologists
|
BIOCHEMISTRY AND ENZYMOLOGY |
In Vivo and in Vitro Studies of Glucose-6-Phosphate Dehydrogenase from Barley Root Plastids in Relation to Reductant Supply for NO2- Assimilation
D. P. Wright, H. C. Huppe and D. H. Turpin
Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6
Pyridine nucleotide pools were measured in intact plastids from roots of
barley (Hordeum vulgare L.) during the onset of NO2- assimilation and
compared with the in vitro effect of the NADPH/NADP ratio on the activity
of plastidic glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) from
N-sufficient or N-starved roots. The NADPH/NADP ratio increased from 0.9 to
2.0 when 10 mM glucose-6-phosphate was supplied to intact plastids. The
subsequent addition of 1 mM NaNO2 caused a rapid decline in this ratio to
1.5. In vitro, a ratio of 1.5 inactivated barley root plastid G6PDH by
approximately 50%, suggesting that G6PDH could remain active during NO2-
assimilation even at the high NADPH/NADP ratios that would favor a
reduction of ferredoxin, the electron donor of NO2- reductase. Root plastid
G6PDH was sensitive to reductive inhibition by dithiothreitol (DTT), but
even at 50 mM DTT the enzyme remained more than 35% active. In root
plastids from barley starved of N for 3 d, G6PDH had a substantially
reduced specific activity, had a lower Km for NADP, and was less inhibited
by DTT than the enzyme from N-sufficient root plastids, indicating that
there was some effect of N starvation on the G6PDH activity in barley root
plastids.
This article has been cited by other articles:
|
|
|
|
 
S. Wakao, C. Andre, and C. Benning
Functional Analyses of Cytosolic Glucose-6-Phosphate Dehydrogenases and Their Contribution to Seed Oil Accumulation in Arabidopsis
Plant Physiology,
January 1, 2008;
146(1):
277 - 288.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. G. Bowsher, A. E. Lacey, G. T. Hanke, D. T. Clarkson, L. R. Saker, I. Stulen, and M. J. Emes
The effect of Glc6P uptake and its subsequent oxidation within pea root plastids on nitrite reduction and glutamate synthesis
J. Exp. Bot.,
March 1, 2007;
58(5):
1109 - 1118.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
Y. Liu, R. Wu, Q. Wan, G. Xie, and Y. Bi
Glucose-6-Phosphate Dehydrogenase Plays a Pivotal Role in Nitric Oxide-Involved Defense Against Oxidative Stress Under Salt Stress in Red Kidney Bean Roots
Plant Cell Physiol.,
March 1, 2007;
48(3):
511 - 522.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Lohse, W. Schliemann, C. Ammer, J. Kopka, D. Strack, and T. Fester
Organization and Metabolism of Plastids and Mitochondria in Arbuscular Mycorrhizal Roots of Medicago truncatula
Plant Physiology,
September 1, 2005;
139(1):
329 - 340.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Esposito, G. Guerriero, V. Vona, V. Di Martino Rigano, S. Carfagna, and C. Rigano
Glutamate synthase activities and protein changes in relation to nitrogen nutrition in barley: the dependence on different plastidic glucose-6P dehydrogenase isoforms
J. Exp. Bot.,
January 1, 2005;
56(409):
55 - 64.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. Hauschild and A. von Schaewen
Differential Regulation of Glucose-6-Phosphate Dehydrogenase Isoenzyme Activities in Potato
Plant Physiology,
September 1, 2003;
133(1):
47 - 62.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. Yonekura-Sakakibara, Y. Onda, T. Ashikari, Y. Tanaka, T. Kusumi, and T. Hase
Analysis of Reductant Supply Systems for Ferredoxin-Dependent Sulfite Reductase in Photosynthetic and Nonphotosynthetic Organs of Maize
Plant Physiology,
March 1, 2000;
122(3):
887 - 894.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Berkemeyer, R. Scheibe, and O. Ocheretina
A Novel, Non-redox-regulated NAD-dependent Malate Dehydrogenase from Chloroplasts of Arabidopsis thaliana L.
J. Biol. Chem.,
October 23, 1998;
273(43):
27927 - 27933.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
