Linked Life Data

9600976

Source:http://linkedlifedata.com/resource/pubmed/id/9600976

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
1998-6-22
pubmed:abstractText
Sulfite oxidase catalyzes the terminal reaction in the degradation of sulfur amino acids. Genetic deficiency of sulfite oxidase results in neurological abnormalities and often leads to death at an early age. The mutation in the sulfite oxidase gene responsible for sulfite oxidase deficiency in a 5-year-old girl was identified by sequence analysis of cDNA obtained from fibroblast mRNA to be a guanine to adenine transition at nucleotide 479 resulting in the amino acid substitution of Arg-160 to Gln. Recombinant protein containing the R160Q mutation was expressed in Escherichia coli, purified, and characterized. The mutant protein contained its full complement of molybdenum and heme, but exhibited 2% of native activity under standard assay conditions. Absorption spectroscopy of the isolated molybdenum domains of native sulfite oxidase and of the R160Q mutant showed significant differences in the 480- and 350-nm absorption bands, suggestive of altered geometry at the molybdenum center. Kinetic analysis of the R160Q protein showed an increase in Km for sulfite combined with a decrease in kcat resulting in a decrease of nearly 1,000-fold in the apparent second-order rate constant kcat/Km. Kinetic parameters for the in vitro generated R160K mutant were found to be intermediate in value between those of the native protein and the R160Q mutant. Native sulfite oxidase was rapidly inactivated by phenylglyoxal, yielding a modified protein with kinetic parameters mimicking those of the R160Q mutant. It is proposed that Arg-160 attracts the anionic substrate sulfite to the binding site near the molybdenum.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/9600976-1587808, http://linkedlifedata.com/resource/pubmed/commentcorrection/9600976-302914, http://linkedlifedata.com/resource/pubmed/commentcorrection/9600976-3374389, http://linkedlifedata.com/resource/pubmed/commentcorrection/9600976-509724, http://linkedlifedata.com/resource/pubmed/commentcorrection/9600976-5723461, http://linkedlifedata.com/resource/pubmed/commentcorrection/9600976-6651793, http://linkedlifedata.com/resource/pubmed/commentcorrection/9600976-6960353, http://linkedlifedata.com/resource/pubmed/commentcorrection/9600976-7623441, http://linkedlifedata.com/resource/pubmed/commentcorrection/9600976-7656976, http://linkedlifedata.com/resource/pubmed/commentcorrection/9600976-8276806, http://linkedlifedata.com/resource/pubmed/commentcorrection/9600976-8631762, http://linkedlifedata.com/resource/pubmed/commentcorrection/9600976-9428520
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0027-8424
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
95
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6394-8
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Human sulfite oxidase R160Q: identification of the mutation in a sulfite oxidase-deficient patient and expression and characterization of the mutant enzyme.
pubmed:affiliation
Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Case Reports