NECi Superior Stock Nitrate Reductase

Nitrate Reductase is an enzyme

(to view the datasheets download Adobe Acrobat PDF Reader)

YNaR1 (click to see datasheet) EC 1.7.1.2

 AtNaR2 (click to see datasheet) EC 1.7.1.1

For Prices: NECi 2009 Catalog

A Model of the enzyme nitrate reductase is shown here.
(For More information see Reference 6 below)

Revised and Updated: 12/17/2008                                                                  1.888.NITRATE  www.nitrate.com

      The Nitrate Elimination Co., Inc.
    Green Chemistry for Nitrate Detection
                              Biotechnology People Can Use

NECi now produces two forms of recombinant enzyme Nitrate Reductase (NaR) :

• Yeast NAD(P)H: NaR - called YNaR1

• Plant NADH: NaR - called AtNaR2

Both forms are "Superior Stock NaR" since they are more stable and more robust forms of the enzyme than found from natural sources (1, 2).  Both Superior Stock NaRs are recombinantly manufactured in Pichia pastoris.  These isoenzymes are made in large quantities, with consistent properties, and low production cost. Thus, both YNaR1 and AtNaR2 are analytical grade enzymes ready to be used in analytical chemical analysis of water and other aqueous solutions.

NECi has been championing enzyme-based nitrate analysis for a number of years, since 1993.  Our original product was the nitrate reductase (NaR) naturally present in corn (Zea mays) seedlings.  Building on years of academic research, we made purified and stabilized NADH-nitrate reductase commercially available for nitrate analysis.  It was clear from early on that anticipated demand could not be met using the native enzyme.  Efforts to develop more reliable recombinant sources of this enzyme were initiated in earnest in 1999, with funding from the Small Business Innovation Research (SBIR) program of the National Institutes of Health.   Recombinant enzymes can be produced under the stringently controlled conditions required to meet today’s QA/QC standards, and production is scalable to meet demand.   In addition, their underlying genes can be modified to facilitate purification and, sometimes, to improve functionality.

 Today NECi produces two different nitrate reductase enzymes: YNaR1, introduced in 2002, and AtNaR2, introduced in 2005.  Both forms of NaR have shelf-life and working solution stability characteristics suited to virtually any lab or field environment.  They differ mainly in operation temperature range.  For applications where the analysis is run between 5 – 30C, YNaR1 is better.  For applications at physiological temperatures or in the range of 20 – 45 C, AtNaR2 is best.  AtNaR2 is slightly more suited to high salt (sodium chloride) environments.

 A major advantage of enzyme-based nitrate analysis over standard chemical methods is sensitivity, which allows a small sample size in relation to the total assay volume.  In most cases, potential interferences such as pH extremes and turbidity are diluted out.  The selectivity of enzymatic reactions means that fewer compounds will interfere, permitting analysis in complex matrices with little sample preparation required.  Their high specificity reduces false positives.

Superior Stock NaRs have been shown to effective as catalysts for the NECi NaR Nitrate Analysis Method (1, 2).  Superior Stock NaRs work well in automated analyzers as shown by Patton and coworkers at USGS (3) and by Lachat Instruments (4).  Recently, the NECi NaR Nitrate Analysis Method was "qualified" on discrete analyzers using YNaR1 at room temperature (4) and AtNaR2 at 37°C (5).

Superior Stock NaRs, YNaR1 and AtNaR2, are the highest specific activity NaRs (ie. most highly purified) commercially available, anywhere in the world.  Superior Stock NaR forms are highly stable and can be shipped at room temperature. Since NECi YNaR1 and AtNaR2 utilize NADH as electron donor to drive nitrate reduction, they are less expensive to use than NADPH-dependent fungal NaR forms. 

For more information on the properties of this unique enzyme, see the detailed review of the biochemistry of NaR published by W. H. Campbell (6).   

References:

1. Barbier, Guillaume G., and Wilbur H. Campbell (2000) Expression of Pichia angusta nitrate reductase (YNaR1) in Pichia pastoris.  Current Topics in Gene Expression Systems: Program and Abstracts, Abstract # PY4, p. 64. 

2. Campbell, Wilbur H., P Song, GG Barbier (2006) Nitrate Reductase for Nitrate Analysis in Water. Environmental Chemistry Letters, 4: 69-73. Download PDF.

3. Campbell, Wilbur H, T Kinnunen-Skidmore, MJ Brodeur-Campbell & ER Campbell (2004) New and improved nitrate reductase for enzymatic nitrate analysis.  American Laboratory 22(10): 12. read it

4. Campbell, Wilbur H., Ellen R. Campbell, Lynn Egan (2006) Green Chemistry Nitrate Determination: An Alternative Nitrate Analysis Method. American Laboratory, February, 2006. Download PDF

5. Patton, C. J., et al. (2006) Nitrate Analysis with Nitrate Reductase on the Discrete Analyzer. In preparation. See: http://pubs.acs.org/subscribe/journals/esthag-a/40/i03/html/020106news4.html

6. Campbell, Wilbur H. (1999) Nitrate Reductase Structure, Function and Regulation: Bridging the Gap between Biochemistry and Physiology, Annual Review of Plant Physiology and Plant Molecular Biology 50:277-303.

To Order: Call toll-free 1-888-NITRATE (648-7283)
 

• YNaR1 Datasheet
• AtNaR2 Datasheet

(to view the datasheets download Adobe Acrobat PDF Reader)
 

Ways to use NaR in various applications:

• Nitrate Testing - NECi now uses Superior Stock NaR in all NTK products
• Automated Nitrate Analysis - NECi Superior Stock NaR is part of a system for automated nitrate analysis developed by NECi and USGS (see ref. #2 above) ARK for automated nitrate analysis
• Bio-Medical Research - NECi Superior Stock NaR is currently used by several companies making Nitric Oxide Test Kits and you can make your own "NO" test kits by using NECi L-NTK or M-NTK and published protocols
• Plant Biochemistry - Many researchers use NECi Corn leaf NaR (see below) for various studies of plant biochemistry and physiology - you can order it from NECi directly or from Sigma-Aldrich (corn leaf NaR in dry form - Prod # N9523; or in solution stabilized with glycerol and BSA = Prod # N2397). Also available Antibodies for NaR
• Nitrate Removal - NECi EzNET® is one approach, but others use NaR to convert nitrate to nitrite and then use a chemical or other method for further reduction - why not try NECi Superior Stock NaR for your nitrate removal problem solver...

To Order: Call toll-free 1-888-NITRATE (648-7283)