Linked Life Data

12429490

Source:http://linkedlifedata.com/resource/pubmed/id/12429490

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
2002-11-13
pubmed:abstractText
The objective of this study was to investigate the presence of amino acid transporters on the corneal epithelium and to enhance corneal drug absorption through prodrug modification targeted to the amino acid transporters. SIRC was used as a model cell line representing the corneal epithelium. Uptake studies were carried out using [3H] L-tyrosine at 37 degrees C. Temperature, energy and pH dependence studies were carried out. The uptake seems to be composed of a major saturable and minor non-saturable component (V(max) =2.9+/-0.62 nmoles/min/mg protein, K(m) =71+/-21 microM, K(d) =2.6+/-0.6 nl/min/mg protein). No significant inhibition of uptake was observed in the presence of metabolic inhibitors or in the absence of sodium. Competitive inhibition studies were performed in the presence of various amino acids and model tyrosine conjugates (p-nitro and p-chloro benzyl ether conjugate of L-tyrosine). Uptake was inhibited by neutral aromatic and large neutral aliphatic amino acids. L-Tyrosine uptake was inhibited by its ether conjugates in a concentration dependent manner suggesting that these compounds may be sharing the same transport mechanism. This study provides biochemical evidence of the presence of a large neutral amino acid transport system on the corneal epithelium, which may be utilized to enhance the corneal drug transport.
pubmed:grant
pubmed:language
eng
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:author
pubmed:copyrightInfo
Copyright 2002 Elsevier Science B.V.
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
115-25
pubmed:dateRevised
2007-11-14
pubmed:articleTitle
Carrier mediated uptake of L-tyrosine and its competitive inhibition by model tyrosine linked compounds in a rabbit corneal cell line (SIRC)--strategy for the design of transporter/receptor targeted prodrugs.
pubmed:affiliation
Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 5005 Rockhill Road, Kansas City, MO 64110-2499, USA.