Linked Life Data

2009922

Source:http://linkedlifedata.com/resource/pubmed/id/2009922

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1991-5-9
pubmed:abstractText
Dihydrofolate reductase (DHFR) from extracts of Mycobacterium smegmatis strain mc2(6) and trimethoprim-resistant mutant mc2(26) was purified to homogeneity. In crude extracts, the specific activity of the enzyme from the trimethoprim resistant strain was comparable to that from the sensitive strain. The DHFR from both sources was purified using affinity chromatography on MTX-Sepharose followed by Mono Q FPLC. The enzyme has an apparent molecular mass of 23 kDa from gel filtration on Sephadex G-100 and from SDS-PAGE. Amino terminal sequence analysis showed homology with DHFRs from a subset of other gram-positive organisms. The purified enzyme from the trimethoprim-sensitive organism exhibited Km values for H2folate and NADPH of 0.68 +/- 0.2 microM and 21 +/- 4 microM, respectively. The Km values for H2folate and NADPH for the enzyme from the drug-resistant organism were 1.8 +/- 0.4 microM and 5.3 +/- 1.5 microM, respectively. A kcat of 4.5 sec-1 was determined for the DHFR from both sources. The enzyme from both sources was competitively inhibited by pyrimethamine and trimethoprim. The Ki value of trimethoprim, for the enzyme from the drug-resistant organism was about six-fold higher than for the enzyme from drug-sensitive strain. Our data suggest that mutation of DHFR contributes to trimethoprim resistance in the mc2(26) strain of M. smegmatis.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0014-4894
pubmed:author
pubmed:issnType
Print
pubmed:volume
72
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
184-90
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Purification and characterization of dihydrofolate reductase from wild-type and trimethoprim-resistant Mycobacterium smegmatis.
pubmed:affiliation
Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't