Linked Life Data

2139607

Source:http://linkedlifedata.com/resource/pubmed/id/2139607

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1990-6-1
pubmed:abstractText
Two nitrate reductases, nitrate reductase A and nitrate reductase Z, exist in Escherichia coli. The nitrate reductase Z enzyme has been purified from the membrane fraction of a strain which is deleted for the operon encoding the nitrate reductase A enzyme and which harbours a multicopy plasmid carrying the nitrate reductase Z structural genes; it was purified 219 times with a yield of about 11%. It is an Mr-230,000 complex containing 13 atoms iron and 12 atoms labile sulfur/molecule. The presence of a molybdopterin cofactor in the nitrate reductase Z complex was demonstrated by reconstitution experiments of the molybdenum-cofactor-deficient NADPH-dependent nitrate reductase activity from a Neurospora crassa nit-1 mutant and by fluorescence emission and excitation spectra of stable derivatives of molybdoterin extracted from the purified enzyme. Both nitrate reductases share common properties such as relative molecular mass, subunit composition and electron donors and acceptors. Nevertheless, they diverge by two properties: their electrophoretic migrations are very different (RF of 0.38 for nitrate reductase Z versus 0.23 for nitrate reductase A), as are their susceptibilities to trypsin. An immunological study performed with a serum raised against nitrate reductase Z confirmed the existence of common epitopes in both complexes but unambiguously demonstrated the presence of specific determinants in nitrate reductase Z. Furthermore, it revealed a peculiar aspect of the regulation of both nitrate reductases: the nitrate reductase A enzyme is repressed by oxygen, strongly inducible by nitrate and positively controlled by the fnr gene product; on the contrary, the nitrate reductase Z enzyme is produced aerobically, barely induced by nitrate and repressed by the fnr gene product in anaerobiosis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
188
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
679-87
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Purification and further characterization of the second nitrate reductase of Escherichia coli K12.
pubmed:affiliation
Centre National de la Recherche Scientifique, Laboratoire de Chimie Bactérienne, Marseille, France.
pubmed:publicationType
Journal Article