scholarly journals Biphasic Kinetic Behavior of Nitrate Reductase from Heterocystous, Nitrogen-Fixing Cyanobacteria

1992 ◽  
Vol 100 (1) ◽  
pp. 157-163 ◽  
Author(s):  
José Martin-Nieto ◽  
Enrique Flores ◽  
Antonia Herrero
Keyword(s):  
Nitrate Reductase ◽  
Kinetic Behavior ◽  
Nitrogen Fixing ◽  
Biphasic Kinetic

Biphasic kinetic behavior of rat cytochrome P-4501A1-dependent monooxygenation in recombinant yeast microsomes

2000 ◽  
Vol 1481 (2) ◽  
pp. 265-272 ◽  
Author(s):  
Kuniyo Inouye ◽  
Toru Mizokawa ◽  
Akitoshi Saito ◽  
Ben’ichiro Tonomura ◽  
Hideo Ohkawa
Keyword(s):  
Recombinant Yeast ◽  
Kinetic Behavior ◽  
Biphasic Kinetic

Standardization of Suitable Substrate and Buffer Solutions for Optimum in-vivo Nitrate Reductase Activity in the Leaves of Sesbania rostrata Bremek. and Oberm.

2016 ◽  
Vol 39 (2) ◽  
pp. 121-124
Author(s):  
S.P. Chaukiyal ◽  
Vandana ◽  
Poornima Uniyal
Keyword(s):  
Nitrate Reductase ◽  
Phosphate Buffer ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Sesbania Rostrata ◽  
Nitrogen Fixing ◽  
Fast Growing ◽  
Buffer Solutions ◽  
Substrate Concentrations

Sesbania rostrata Bremek. and Oberm. is a multipurpose and exceptionally fast growing nitrogen fixing plant. In this study a protocol for the standardization of in-vivo nitrate reductase (NR) assay with respect to substrate concentrations along with buffer pH and concentrations was carried out in the leaves of S. rostrata. Different substrate (KNO3) concentration ( i.e. 0.025M, 0.05M, 0.10M, 0.15M, 0.20M ) were tried against phosphate buffer (KH2PO4) solutions with different pH (6.5, 7.0, 7.5, 7.6, 7.7, 7.8 ). Maximum leaf in-vivo nitrate reductase activity was observed in 0.10 M phosphate buffer (KH2PO4) concentration of pH 7.5 with 0.15M substrate (KNO3) concentration.

The Rhizobium -legume symbiosis

1979 ◽  
Vol 204 (1155) ◽  
pp. 219-233 ◽  
Keyword(s):  
Nitrate Reductase ◽  
Energy Supply ◽  
Physiological Changes ◽  
Nitrogen Fixing ◽  
Fixed Nitrogen ◽  
Nitrogen Fixing Bacteria ◽  
Free Living ◽  
Legume Symbiosis

physiological changes involved in the differentiation of bacteroids within the nodule. Certainly the addition of nodules to fixed nitrogen in the form of NH + 4 or NO - 3 does repress N 2 -ase, although the concentrations required are greater than for repression in free-living nitrogen-fixing bacteria (Klamberger 1977). Various hypotheses have been put forward to account for the repression of N 2 -ase activity in the nodule. One hypothesis was that in the presence of exogenous nitrate the plant’s nitrate reductase competed for photosynthate, thereby rendering N 2 -ase inactive because it was starved of an energy supply (Oghoghorie & Pate 1971). Evidence against this was the finding (Chen & Phillips 1976) that addition of NO - 3 to pea leaves did not inhibit N 2 -ase, and that, if the plants were exposed to an atmosphere enriched with CO 2 , the extent of N 2 -ase repression when NO - 3 was applied to the roots was the same as in a normal atmosphere despite the increase in the plants’ photosynthetic capability. Thus, if there is any competition for photosynthate between N 2 -ase and nitrate reductase, it must be localized. This model does not explain why NH + 4 is also efficient as a repressor of N 2 -ase. Recently Bisseling, van den Bos & van Kamman (1978) showed that under conditions where NH 4 NO 3 repressed N 2 -ase activity in pea nodules, it did not affect synthesis of the enzyme. They proposed that the inhibition of N 2 -ase in the nodule was indirect, being mediated by an inhibition of the synthesis of leg-haemoglobin.

scholarly journals Biphasic Kinetic Behavior of E. coli WrbA, an FMN-Dependent NAD(P)H:Quinone Oxidoreductase

PLoS ONE ◽  
2012 ◽  
Vol 7 (8) ◽  
pp. e43902 ◽  
Author(s):  
Iryna Kishko ◽  
Balasubramanian Harish ◽  
Vasilina Zayats ◽  
David Reha ◽  
Brian Tenner ◽  
...  
Keyword(s):  
Kinetic Behavior ◽  
E Coli ◽  
Biphasic Kinetic
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