scholarly journals 15N-Ammonia Assimilation, 2-Oxoglutarate Transport, and Glutamate Export in Spinach Chloroplasts in the Presence of Dicarboxylates in the Light

1987 ◽  
Vol 85 (3) ◽  
pp. 621-625 ◽  
Author(s):  
K. C. Woo ◽  
F. A. Boyle ◽  
I. U. Flugge ◽  
Hans W. Heldt
Keyword(s):  
Ammonia Assimilation ◽  
Spinach Chloroplasts

Ammonia Assimilation and Metabolite Transport in Isolated Chloroplasts. II. Malate Stimulates Ammonia Assimilation in Chloroplasts Isolated From Leaves of Dicotyledonous but Not Monocotyledonous Species

1992 ◽  
Vol 19 (6) ◽  
pp. 659 ◽  
Author(s):  
JW Yu ◽  
KC Woo
Keyword(s):  
Nutrient Solution ◽  
The Other ◽  
Ammonia Assimilation ◽  
O2 Evolution ◽  
Evolution System ◽  
Metabolite Transport ◽  
Spinach Chloroplasts ◽  
Counter Ion ◽  
High Nutrient ◽  
Isolated Chloroplasts

Malate stimulated NH3 assimilation, as determined by a (2-oxoglutarate, NH3)-dependent O2 evolution system, by up to 3-fold in chloroplasts isolated from leaves of dicot but not monocot species. This difference was apparently correlated with the endogenous metabolite pools present in these chloroplast preparations. During NH3 assimilation the glutamate and glutamine pools were large in spinach (dicot) but small in oat chloroplasts. The reverse was the case for the 2-oxoglutarate (2-OG) pool. The addition of malate substantially increased the glutamate, glutamine and 2-OG pools in spinach chloroplasts but had little effect in oat chloroplasts. This suggests that the supply of 2-OG was apparently limiting NH3 assimilation in spinach chloroplasts. Malate increased this supply and, consequently, stimulated NH3 assimilation. On the other hand, NH3 assimilation in oat chloroplasts seemed to be limited by the supply of glutamate and glutamine which could not be overcome by the addition of malate. Chloroplasts were also isolated from oat seedlings watered with high nutrient solution. The rates of NH3 assimilation in these organelles exceeded those obtained in spinach chloroplasts. But the addition of malate had little effect on (2-OG, NH3)-dependent O2 evolution in these oat chloroplasts. Since malate did not inhibit this activity it is conceivable that it still might play a role, albeit a 'passive' role, in serving as a counter-ion for 2-OG uptake via the 2-OG translocator and glutamate export via the Dct translocator during NH3 assimilation.

Ammonia Assimilation and Metabolite Transport in Isolated Chloroplasts. I. Kinetic Measurement of 2-Oxoglutarate and Malate Uptake Via the 2-Oxoglutarate Translocator in Oat and Spinach Chloroplasts

1992 ◽  
Vol 19 (6) ◽  
pp. 653 ◽  
Author(s):  
JW Yu ◽  
KC Woo
Keyword(s):  
Double Layer ◽  
Ammonia Assimilation ◽  
Kinetic Properties ◽  
Kinetic Measurement ◽  
Transport Activity ◽  
Metabolite Transport ◽  
Spinach Chloroplasts ◽  
Dicarboxylate Transport ◽  
Push And Pull ◽  
Isolated Chloroplasts

The stable double-layer silicone centrifugation system was used to determine the kinetic properties of the 2-oxoglutarate (2-OG) translocator in isolated oat and spinach chloroplasts. The uptake of [14C]2-OG and [14C]malate via the 2-OG translocator were measured in the presence of 20 mM glutamate in chloroplasts preloaded with unlabelled 2-OG. The characteristics of the general dicarboxylate (Dct) translocator were also determined using chloroplasts preloaded with glutamate. The Vmax values obtained for transport activity via the 2-OG translocator in oat and spinach chloroplasts exceeded 150 μmol mg-1 Chl h-1 and for the Dct translocator less than 100 μmol mg-1 Chl h-1. The K� (malate) values of the 2-OG and Dct translocators also showed large differences in the two species. In spinach chloroplasts they were 2.7 and 0.6 mM for the 2-OG and Dct translocators respectively whereas, in oat chloroplasts the corresponding values were 2.7 and 1.4 mM. This suggests that, in spinach, malate would be transported into the chloroplasts preferentially via the Dct translocator, thus providing a kinetic basis for the 'push and pull' mechanism proposed for dicarboxylate transport during photorespiratory NH3 recycling in the 2-translocator model.

scholarly journals Photophosphorylation by Digitonin-fragmented Spinach Chloroplasts

1959 ◽  
Vol 234 (8) ◽  
pp. 2196-2201 ◽  
Author(s):  
Jane Koukol ◽  
C.T. Chow ◽  
Birgit Vennesland
Keyword(s):  
Spinach Chloroplasts

scholarly journals Oxidative Photosynthetic Phosphorylation by Spinach Chloroplasts

1959 ◽  
Vol 234 (8) ◽  
pp. 2205-2210
Author(s):  
David W. Krogmann ◽  
Birgit Vennesland
Keyword(s):  
Spinach Chloroplasts

scholarly journals Role of AMP in photophosphorylation by spinach chloroplasts.

1979 ◽  
Vol 254 (19) ◽  
pp. 9500-9508
Author(s):  
M.A. Tiefert ◽  
E.N. Moudrianakis
Keyword(s):  
Spinach Chloroplasts

Reconstitution of amino acid synthesis by combining spinach chloroplasts with other leaf organelles

1979 ◽  
Vol 18 (7) ◽  
pp. 1109-1111 ◽  
Author(s):  
Barbara Buchholz ◽  
Brigitte Reupke ◽  
Horst Bickel ◽  
Gernot Schultz
Keyword(s):  
Amino Acid ◽  
Acid Synthesis ◽  
Amino Acid Synthesis ◽  
Spinach Chloroplasts

scholarly journals Univalent Reduction of Molecular Oxygen by Spinach Chloroplasts on Illumination

1974 ◽  
Vol 249 (7) ◽  
pp. 2175-2181
Author(s):  
Kozi Asada ◽  
Kuniaki Kiso ◽  
Kyoko Yoshikawa
Keyword(s):  
Molecular Oxygen ◽  
Spinach Chloroplasts
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