Linked Life Data

1902381

Source:http://linkedlifedata.com/resource/pubmed/id/1902381

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
1991-6-6
pubmed:abstractText
Fluorescein-methotrexate, a derivative in which the fluorophore is linked via a diaminopentane spacer to either the alpha- or gamma-carboxyl group of the glutamate moiety in the drug [Gapski et al. (1975) J. Med. Chem. 18, 526-528], has been synthesized by an improved procedure and separated by DEAE-Trisacryl chromatography into the alpha- and gamma-isomers (alpha-F-MTX and gamma-F-MTX). Each isomer was characterized by mass spectrometry, elemental analysis, absorbance spectrum, TLC, and reversed-phase HPLC. Identity of the isomers was established by the following enzymatic criteria: (a) gamma-F-MTX (but not the alpha-isomer) was hydrolyzed at the pteroate-glutamate bond by carboxypeptidase G2 to yield 4-amino-4-deoxy-10-methylpteroate and gamma-glutamyldiaminopentane-fluorescein; and (b) gamma-F-MTX was a much better inhibitor of human dihydrofolate reductase than the alpha-isomer (Ki values of 0.079 and 4.6 nM). alpha- and gamma-F-MTX were comparable as inhibitors (Ki values of 1.6 and 0.6 microM) of the transport system for reduced folates and MTX in L1210 cells, but the transporter in Lactobacillus casei was inhibited only by the gamma-isomer (Ki = 4.3 microM). The gamma-isomer, therefore, was selected for covalent labeling of proteins. When L. casei folate transport protein (18 kDa) was treated with gamma-F-MTX that had been activated with N-hydroxysuccinimide (NHS), the protein was readily visualized as a fluorescent band on SDS-PAGE electrophoretograms. The probe was also able to detect the transporter in membranes.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4573-80
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Affinity labeling of folate transport proteins with the N-hydroxysuccinimide ester of the gamma-isomer of fluorescein-methotrexate.
pubmed:affiliation
Department of Molecular and Experimental Medicine, Research Institute of Scripps Clinic, La Jolla, California 92037.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't