Linked Life Data

1990004

Source:http://linkedlifedata.com/resource/pubmed/id/1990004

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1991-3-7
pubmed:abstractText
delta-Aminolevulinic acid (ALA) is the first committed precursor for tetrapyrrole biosynthesis. ALA formation in Escherichia coli occurs in a tRNA-dependent three-step conversion from glutamate. Glu-tRNA reductase is the key enzyme in this pathway. E. coli K12 contains two Glu-tRNA reductase activities which differ in their molecular weights. Here we describe the purification of one of these enzymes. Four different chromatographic separations yielded a nearly homogeneous protein. Its apparent molecular mass under denaturing (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) and nondenaturing conditions (rate zonal sedimentation and gel filtration) is 85,000 +/- 5,000 Da. This indicates a monomeric structure for the active enzyme. Gel filtration and glycerol gradient centrifugation indicate that the other activity has a molecular mass of 45,000 +/- 5,000 Da. In the presence of NADPH both enzyme activities converted E. coli Glu-tRNA(2Glu) to glutamate 1-semialdehyde. Addition of GTP or hemin did not affect the reductase activity. Both enzymes display sequence-specific recognition of tRNA; E. coli Glu-tRNA(2Glu) is a good substrate while the Chlamydomonas reinhardtii, Bacillus subtilis, and Synechocystis Glu-tRNA(Glu) species are poorly recognized.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
266
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2542-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Two glutamyl-tRNA reductase activities in Escherichia coli.
pubmed:affiliation
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.