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Quan, De,Nagarale, R. K.,Shin, Woonsup WILEY-VCH Verlag 2010 Electroanalysis Vol.22 No.20
<P>Copper containing nitrite reductase (Cu-NiR) and viologen-modified sulfonated polyaminopropylsiloxane (PAPS-SO<SUB>3</SUB>H-V) were co-immobilized on glassy carbon electrode (GCE) by hydrophilic polyurethane (HPU) drop-coating, and the electrode was tested as a reagentless electrochemical biosensor for nitrite detection. The newly synthesized PAPS-SO<SUB>3</SUB>H-V as an electron transfer (ET) mediator between electrode and NiR was effective, and could be effectively immobilized in HPU membrane. The NiR and PAPS-SO<SUB>3</SUB>H-V co-immobilized GCE used as a nitrite biosensor showed the following performance factors: sensitivity=12.0 nA μM<SUP>−1</SUP>, limit of detection (LOD)=60 nM (S/N=3), linear response range=0–18 μM (r<SUP>2</SUP>=0.996) and response time (t<SUB>90%</SUB>)=60 s, respectively. Lineweaver–Burk plot shows that apparent Michaelis–Menten constant (K<TEX>$\rm{{_{M}^{app}})}$</TEX> is 101 μM. Storage stability of the sensor is 51 days (80% of initial activity) in condition of storing in ambient air at room temperature. The sensor showed a relative standard deviation (RSD) of 3.2% (n=5) even in condition of injection of 1 μM nitrite. Interference study showed that common anions in water sample such as chlorate, chloride, sulfate and sulfite do not interfere with the nitrite detection. However, nitrate interfered with a relative sensitivity of 80% due to inherent character of the enzyme used.</P>
Jeongsu KIM,Jungheon LEE 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
The aim of this study is to determine the activity of enzymes by soil microorganisms and to develop a HONO production model according to the change in nitrogen concentration in the soil. Most plants absorb nitrogen in the form of nitrate (NO₃⁻) after ammonium (NH₄⁺) is converted into NO₃⁻ by nitrifying bacteria. The NO₃⁻ is reduced to nitrite (NO₂⁻) by nitrate reductase, which is also reduced to NH₄⁺ by nitrite reductase. It is important for the development of HONO model to measure the concentration of a nitrogen source in the soil. Soil samples were collected from Jeollanam-do area. Quantitative analysis of NH₄⁺ was performed using the indophenol method. For quantitative analysis of NO₂⁻ and NO₃⁻, HPLC analysis at 214 nm (Sphereclone Sax column) was performed. The LOD and LOQ of NO₂⁻ and NO₃⁻ were lower than 0.1 ppm and 0.2 ppm, respectively. The concentration decreased with increasing soil depth. Soil samples from soybean fields had a reduced NO₃⁻ concentration from 111.60 ppm to 46.20 ppm. We plan to complete the HONO emission model by measuring the change in the nitrogen concentration and the activity of related enzymes in Korean soil and estimating the reaction rate constant.
A Comparison of Wild and Cultivated Strawberries for Nitrogen Uptake and Reduction
Toktam Taghavi,Kevin M. Folta 한국원예학회 2014 Horticulture, Environment, and Biotechnology Vol.55 No.3
The strawberry (Fragaria × ananassa) requires substantial amounts of nitrogen to produce reasonable yields. Wild strawberries (e.g. F. virginiana) grow in soils in the absence of supplemental nitrogen and may possess desirablegenes, alleles or expression patterns that support efficient nitrogen uptake and assimilation. The F. virginiana accessionsand cultivated materials were used to monitor the accumulation kinetics of five nitrate responsive genes (nitrate transporter,NRT1.1; nitrate reductase, NIA1; nitrite reductase, NiR; ferredoxin NADP reductase, FNR; and transketolase, TK) alongwith nitrate reductase activity. The results revealed expression patterns that were reminiscent of those observed inArabidopsis. Wild strawberries exhibited higher transcript accumulation for all genes examined except the nitrate transporter,compared to cultivated materials. Nitrate reductase activity (NRA) did not change in roots but increased in leaves inresponse to nitrate. Most wild genotypes had higher NRA in aerial tissues compared to cultivated materials. Comparisons of enzyme activity to transcript accumulation kinetics suggest that available nitrate reductase is activatedand not likely synthesized de novo, suggesting that some wild accessions may possess enhanced nitrogen assimilationmechanisms. These attributes may be useful to breeding programs in the design of elite plants that may make moreefficient use of fertilizers.
Effects of Electron Donors on Nitrate Removal by Nitrate and Nitrite Reductases
Yoo, Young-Je,Sung, Dong-Won,Song, Seung-Hoon,Kim, Ji-Hyeon The Korean Society for Biotechnology and Bioengine 2002 Biotechnology and Bioprocess Engineering Vol.7 No.2
Effects of artificial electron donors to deliver reducing power on enzymic denitrification were investigated using nitrate reductase and nitrite reductase obtained from Ochrobactrum antroyi. The activity of nitrite reductase in the soluble portion was almost the same as that in the precipitated portion of the cell extract. Nitrate removal efficiency was higher with benzyl viologen than with methyl viologen or NADH as an artificial electron donor. The turn-over numbers of nitrate and nitrite reductase were 14.1 and 1.9 umol of nitrogen reduced/min$.$mg cell extracts, respectively when benzyl viologen was used as an electron donor.
AtSIZ1 Regulates Expression of Nitrite Reductase but Not Its Activity
Park, Bong Soo,Kim, Sung-Il,Seo, Hak Soo The Korean Society for Applied Biological Chemistr 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.2
Plant nitrite reductase (NiR) catalyzes the reduction of nitrite to ammonium. We examined if NiR activity is regulated by sumoylation, and found NiR was not sumoylated by E3 small ubiquitin-related modifier ligase AtSIZ1. However, its transcript level decreased in the siz1-2 mutant, indicating that AtSIZ1 does not directly control NiR activity.
AtSIZ1 Regulates Expression of Nitrite Reductase but Not Its Activity
박봉수,서학수,김성일 한국응용생명화학회 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.2
Plant nitrite reductase (NiR) catalyzes the reduction of nitrite to ammonium. We examined if NiR activity is regulated by sumoylation, and found NiR was not sumoylated by E3 small ubiquitin-related modifier ligase AtSIZ1. However, its transcript level decreased in the siz1-2 mutant, indicating that AtSIZ1 does not directly control NiR activity.