Linked Life Data

1998951

Source:http://linkedlifedata.com/resource/pubmed/id/1998951

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1991-4-9
pubmed:abstractText
Monochlorobimane (MCB) has been used as a glutathione (GSH) specific fluorescent probe capable of delineating GSH heterogeneity in cellular systems. Generally, low concentrations of MCB (less than 50 microM) have been used to quantitatively label GSH in rodent cell lines. Incubation of the hamster cell lines, CHO AB1 and V79, with 10 microM MCB labeled 75 and 39% of the reduced GSH pool, respectively. In contrast, incubation of 7 different human cell lines with 10 microM MCB labeled less than 4% of the total reduced GSH pool. The human cell lines required 1000 microM MCB to label an average of 73% of the GSH pool (range, 60-88%). When using 1000 microM MCB to label GSH, flow cytometry results from 7 different cell lines (human and rodent) were in good agreement with high performance liquid chromatography and standard spectrophotometric analysis with regards to a rank ordering of the GSH content determined for each cell line. The human glutathione S-transferases B2B2, B1B2, psi, pi, and the rat transferases 1-2, 3-3, and 3-4 were isolated and purified for steady state kinetic analysis with MCB and GSH as the primary substrates. The human basic transferases, B1B2 and B2B2, had Km values for MCB of 354 and 283 microM and Vmax values of 33.3 and 34.6 mumol bimane-GSH/min/mg protein, respectively. The rat basic transferase 1-2 showed similar kinetic results with a Km of 199 microM and a Vmax of 35.5 mumol bimane-GSH/min/mg protein. The human neutral transferase (psi) had a Km for MCB of 204 microM with a Vmax of 6.5 mumol bimane-GSH/min/mg protein. In contrast, MCB has a high affinity for the rat neutral transferase with a Km of 2.6 microM and a Vmax of 35.1 mumol bimane-GSH/min/mg protein. The human acidic transferase (pi), the predominate transferase found in most human tumor cell lines, has a Km of 264 microM for MCB and a Vmax of 1.99 mumol bimane-GSH/min/mg protein. The kcat/Km values indicated that MCB is an excellent substrate for the rat neutral transferases while the human pi glutathione S-transferase showed the least reactivity. Collectively the data indicate that MCB fails to label GSH at lower concentrations (less than 50 microM) in human cell lines because of the reduced affinity of MCB for the human transferases and possibly also due to differences in glutathione S-transferase isozyme expression between rodent and human cell lines.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0008-5472
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
51
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1606-12
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Differential specificity of monochlorobimane for isozymes of human and rodent glutathione S-transferases.
pubmed:affiliation
Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
pubmed:publicationType
Journal Article