Linked Life Data

1889411

Source:http://linkedlifedata.com/resource/pubmed/id/1889411

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1991-10-15
pubmed:abstractText
The uptake of intracellular putrescine and spermidine was examined in B16 melanoma cells. It was found that difluoromethylornithine preferentially induced putrescine transport (28-fold) compared to that for spermidine (3.5-fold). Putrescine uptake was partially Na+ dependent, whereas spermidine uptake was not. Inhibition studies with the two polyamines showed that putrescine was a poor competitive inhibitor of spermidine uptake, exhibiting a Ki of 69-75 microM, whereas the estimated Km for putrescine uptake was only 5.36 microM. By contrast, spermidine inhibition of putrescine transport produced a non-linear Eadie-Scatchard plot suggesting that putrescine was taken up by a spermidine-sensitive and a spermidine-insensitive process. The estimated spermidine Ki for inhibition of the spermidine-sensitive process was 0.125 microM. Using a series of polypyridinium quaternary salts to inhibit transport, no correlation between inhibition of putrescine uptake and inhibition of spermidine uptake was seen. Finally, the photoaffinity label, 1,12-di(N5-azido-2-nitrobenzoyl)spermine selectively inactivated the putrescine transporter(s) without affecting spermidine uptake. From these observations, it was concluded that multiple polyamine transporters are present on B16 melanoma cells and that separate, distinct transporter(s) account for the uptake of putrescine and spermidine in this cell-line following induction with difluoromethylornithine. The present of different transporters for the two polyamines indicates that expression of uptake activity for putrescine and spermidine may be under separate cellular control.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
200
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
457-62
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Evidence for the existence of distinct transporters for the polyamines putrescine and spermidine in B16 melanoma cells.
pubmed:affiliation
Department of Pharmacology, University of Western Australia, Nedlands.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't