Updated BioCyc iOS App now
available in iTunes store
Updated BioCyc iOS App now
available in iTunes store
Updated BioCyc iOS App now
available in iTunes store
Updated BioCyc iOS App now
available in iTunes store
Updated BioCyc iOS App now
available in iTunes store

MetaCyc Pathway: nitrate reduction II (assimilatory)
Traceable author statement to experimental support

Pathway diagram: nitrate reduction II (assimilatory)

This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.

Synonyms: nitrate assimilation

Superclasses: Degradation/Utilization/AssimilationInorganic Nutrients MetabolismNitrogen Compounds MetabolismNitrate Reduction

Some taxa known to possess this pathway include : Arabidopsis thaliana col

Expected Taxonomic Range: Rhodophyta, Viridiplantae

In plants and algae nitrate is an important source of nitrogen. Nitrate assimilation begins with the uptake of nitrate from the soil by the root. Root epidermal and cortical cells are the first to actively transport nitrate into their cytosols. Nitrate then crosses the endodermis of the root and is released into the xylem. After long distance transport up the xylem, nitrate is again actively transported into the cells of the leaf. Once in the cell, nitrate can be stored in the vacuole (due to toxicity) or reduced to nitrite by the enzyme nitrate reductase (NR).

Four classes of nitrate reductases are known - a eukaryotic class, and three prokaryotic classes. The eukaryotic nitrate reductases are found in plants, algae and fungi, and are involved in assimilation of nitrate. They are composed of two identical subunits, and contain a MoO2-molybdopterin cofactor and an FAD prosthetic group. In general, plant enzymes prefer NADH as the electron donor ( E.C. and fungal enzymes prefer NADPH ( E.C., although some enzymes were reported to accept either of these compounds ( E.C. [Beevers64]. Example for eukaryotic enzymes include the assimilatory nitrate reductase (NADH) from Arabidopsis thaliana and the assimilatory nitrate reductase (NADPH) from Neurospora crassa.

Nitrite is transported into the chloroplast, where it is reduced to ammonia by nitrite reductase (NiR). The final step of the pathway is the incorporation of ammonia into glutamine by glutamine synthetase [Elliot94].

Variants: nitrate reduction I (denitrification), nitrate reduction III (dissimilatory), nitrate reduction IV (dissimilatory), nitrate reduction V (assimilatory), nitrate reduction VI (assimilatory), nitrate reduction VII (denitrification), nitrate reduction VIII (dissimilatory), nitrate reduction IX (dissimilatory), nitrate reduction X (periplasmic, dissimilatory)


Beevers64: Beevers, L, Flesher, D., Hageman, R.H. (1964). "Studies on the pyridine nucleotide specificity of nitrate reductase in higher plants and its relationship to sulfhydryl level." Biochim Biophys Acta 89:453-64. PMID: 14209328

Dey97: Dey, P. M., Harborne, J. B. (1997). "Plant Biochemistry." Academic Press Inc., San Diego, USA.

Elliot94: Elliot M. Meyerowitz, Chris R. Somerville (1994). "Arabidopsis." ISBN 0-87969-428-9, Cold Spring Harbor Laboratory Press Cold Spring Harbor, NY.

Other References Related to Enzymes, Genes, Subpathways, and Substrates of this Pathway

Alibhai94: Alibhai M, Villafranca JJ (1994). "Kinetic and mutagenic studies of the role of the active site residues Asp-50 and Glu-327 of Escherichia coli glutamine synthetase." Biochemistry 33(3);682-6. PMID: 7904829

Amaya05: Amaya KR, Kocherginskaya SA, Mackie RI, Cann IK (2005). "Biochemical and mutational analysis of glutamine synthetase type III from the rumen anaerobe Ruminococcus albus 8." J Bacteriol 187(21);7481-91. PMID: 16237031

Balakrishnan78: Balakrishnan MS, Villafranca JJ (1978). "Distance determinations between the metal ion sites of Escherichia coli glutamine synthetase by electron paramagnetic resonance using Cr(III)--nucleotides as paramagnetic substrate analogues." Biochemistry 17(17);3531-8. PMID: 28753

Bender77: Bender RA, Janssen KA, Resnick AD, Blumenberg M, Foor F, Magasanik B (1977). "Biochemical parameters of glutamine synthetase from Klebsiella aerogenes." J Bacteriol 129(2);1001-9. PMID: 14104

BRENDA14: BRENDA team (2014). Imported from BRENDA version existing on Aug 2014.

CohenKupiec93: Cohen-Kupiec R, Gurevitz M, Zilberstein A (1993). "Expression of glnA in the cyanobacterium Synechococcus sp. strain PCC 7942 is initiated from a single nif-like promoter under various nitrogen conditions." J Bacteriol 175(23);7727-31. PMID: 7902350

Crawford88: Crawford NM, Smith M, Bellissimo D, Davis RW (1988). "Sequence and nitrate regulation of the Arabidopsis thaliana mRNA encoding nitrate reductase, a metalloflavoprotein with three functional domains." Proc Natl Acad Sci U S A 1988;85(14);5006-10. PMID: 3393528

Dahlquist75: Dahlquist FW, Purich DL (1975). "Regulation of Escherichia coli glutamine synthetase. Evidence for the action of some feedback modifiers at the active site of the unadenylylated enzyme." Biochemistry 14(9);1980-9. PMID: 235974

Dhalla94: Dhalla AM, Li B, Alibhai MF, Yost KJ, Hemmingsen JM, Atkins WM, Schineller J, Villafranca JJ (1994). "Regeneration of catalytic activity of glutamine synthetase mutants by chemical activation: exploration of the role of arginines 339 and 359 in activity." Protein Sci 3(3);476-81. PMID: 7912599

Farrington87: Farrington GK, Kumar A, Wedler FC (1987). "Design and synthesis of phosphonate inhibitors of glutamine synthetase." J Med Chem 1987;30(11);2062-7. PMID: 2889829

Gibbs84: Gibbs EJ, Ransom SC, Cuppett S, Villafranca JJ (1984). "Mn-Mn interaction in adenylylated and unadenylylated glutamine synthetase." Biochem Biophys Res Commun 120(3);939-45. PMID: 6145412

Helmward89: Helmward Z "Handbook of Enzyme Inhibitors. 2nd, revised and enlarged edition." Weinheim, Federal Republic of Germany ; New York, NY, USA , 1989.

Hofmann78: Hofmann GE, Glaunsinger WS (1978). "EPR investigation of the Mn(II) binding sites in glutamine synthetase (Escherichia coli W). I. High-affinity binding sites." J Biochem (Tokyo) 83(6);1769-78. PMID: 27502

Hofmann78a: Hofmann GE, Glaunsinger WS (1978). "EPR investigation of the Mn(II) binding sites in glutamine synthetase (Escherichia coli W). II. Intermediate-affinity binding sites." J Biochem (Tokyo) 83(6);1779-82. PMID: 27503

Ishiyama04: Ishiyama K, Inoue E, Watanabe-Takahashi A, Obara M, Yamaya T, Takahashi H (2004). "Kinetic properties and ammonium-dependent regulation of cytosolic isoenzymes of glutamine synthetase in Arabidopsis." J Biol Chem 279(16);16598-605. PMID: 14757761

Johnson: Johnson AK, Schwob JE "Cephalic angiotensin receptors mediating drinking to systemic angiotensin II." Pharmacol Biochem Behav 3(6);1077-84. PMID: 177996

Kingdon67: Kingdon HS, Stadtman ER (1967). "Regulation of glutamine synthetase. X. Effect of growth conditions on the susceptibility of Escherichia coli glutamine synthetase to feedback inhibition." J Bacteriol 94(4);949-57. PMID: 4860919

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Lin78: Lin WS, Kapoor M (1978). "Purification and studies of some physicochemical properties of glutamine synthetase of Neurospora crassa." Can J Biochem 56(10);927-33. PMID: 31969

Listrom97: Listrom CD, Morizono H, Rajagopal BS, McCann MT, Tuchman M, Allewell NM (1997). "Expression, purification, and characterization of recombinant human glutamine synthetase." Biochem J 328 ( Pt 1);159-63. PMID: 9359847

Showing only 20 references. To show more, press the button "Show all references".

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by Pathway Tools version 19.5 (software by SRI International) on Fri Apr 29, 2016, biocyc11.