Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.7.1.4 (nitrite reductase)
 1,847 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A structural gene encoding nitrite reductase (NiR) in bean (Phaseolus vulgaris) has been cloned and sequenced. The NiR gene is present as a single copy encoding a protein of 582 amino acids. The bean NiR protein is synthesized as a precursor with an amino-terminal transit peptide (TP) consisting of 18 amino acid residues. The bean NiR transit peptide shows similarity to the TPs of other known plant NiRs. The NiR gene is expressed in trifoliate leaves and in roots of 20-day old bean plants where transcript accumulation is nitrate-inducible. Gene expression occurs in a circadian rhythm and induced by light in leaves of dark-adapted plants. A particular 100 bp sequence is present in the promoter and in the first intron of the NiR gene. Several copies of this 100 bp sequence are present in the bean genome. Comparisons between the promoter of the bean NiR gene and of two bean nitrate reductase genes (NR1 and NR2) show a limited number of conserved motifs, although the genes are presumed to be co-regulated. Comparisons are also made between the bean NiR promoter and the spinach NiR promoter. Transformation of tobacco plants with the bean NiR promoter fused to the GUS reporter gene (beta-glucuronidase) shows that the bean NiR promoter is nitrate-regulated and that the presence of the 100 bp sequence influences the level of GUS activity. NiR-coding sequences are not required for nitrate regulation but have a quantitative effect on the measured GUS activity.
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PMID:Structure and expression of a nitrite reductase gene from bean (Phaseolus vulgaris) and promoter analysis in transgenic tobacco. 786 86

Banding patterns of nitrate reductase (NR), nitrite reductase (NiR), and glutamine synthetase (GS) from leaves of diploid barley (Hordeum vulgare), tetraploid wheat (Triticum durum), hexaploid wheat (Triticum aestivum), and tetraploid wild oats (Avena barbata) were compared following starch gel electrophoresis. Two NR isozymes, which appeared to be under different regulatory control, were observed in each of the three species. The activity of the more slowly migrating nitrate reductase isozyme (NR1) was induced by NO3- in green seedlings and cycloheximide inhibited induction. However, the activity of the faster NR isozyme (NR2) was unaffected by addition of KNO3, and it was not affected by treatments of cycloheximide or chloramphenicol. Only a single isozyme of nitrite reductase was detected in surveys of three tetraploid and 18 hexaploid wheat, and 48 barley accessions; however, three isozymes associated with different ecotypes were detected in the wild oats. Inheritance patterns showed that two of the wild oat isozymes were governed by a single Mendelian locus with two codominant alleles; however, no variation was detected for the third isozyme. Treatment of excised barely and wild oat seedlings with cycloheximide and chloramphenicol showed that induction of NiR activity was greatly inhibited by cycloheximide, but only slightly by chloramphenicol. Only a single GS isozyme was detected in extracts of green leaves of wheat, barley, and wild oat seedlings. No electrophoretic variation was observed within or among any of these three species. Thus, this enzyme appears to be the most structurally conserved of the three enzymes.
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PMID:Inheritance of nitrite reductase and regulation of nitrate reductase, nitrite reductase, and glutamine synthetase isozymes. 1154 65