Linked Life Data

12603856

Source:http://linkedlifedata.com/resource/pubmed/id/12603856

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2003-2-26
pubmed:abstractText
Biotin is an essential micronutrient for normal cellular function, growth, and development. Biotin deficiency leads to pathologic, dermatologic, and neurocutaneous manifestations in skin and its appendages. Previous studies described the presence of specific biotin transport systems in the epithelia of the intestine, liver, kidney, and placenta, and in blood mononuclear cells. The aim of this study was to examine biotin transport into human keratinocytes. Uptake of [3H]biotin was measured both in the HaCaT cell line and in native keratinocytes in primary culture. Uptake of [3H]biotin (6 nM) in HaCaT cells was linear for up to 5 min of incubation. In the presence of an Na+ gradient total biotin uptake was 4- to 5-fold higher than in the absence of sodium ions. Biotin uptake was not altered by H+ and Cl- gradients. This transport system exhibited a Michaelis-Menten constant for biotin of 22.7+/-1.0 microM and a maximal velocity of 163.6+/-3.5 pmol per 5 min per mg protein. [3H]Biotin uptake (6 nM) was strongly inhibited by lipoic acid (oxidized form, Ki=4.6 microM; reduced form, Ki=11.4 microM), pantothenic acid (Ki=1.2 microM), and desthiobiotin (Ki=15.2 microM), but not by biocytin or biotin methyl ester. Measured at [3H]biotin concentrations of 0.1-10 nM we obtained kinetic evidence for the presence of a second transport component that is saturable at very low biotin concentrations (Kt=2.6+/-0.1 nM). Unlabeled lipoic acid and pantothenic acid (20 nM) did not inhibit the [3H]biotin uptake (1 nM). We conclude that human keratinocytes express the Na+-dependent multivitamin transporter with preference for pantothenate and a very high affinity transport component with specificity for biotin.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0022-202X
pubmed:author
pubmed:issnType
Print
pubmed:volume
120
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
428-33
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Transport of biotin in human keratinocytes.
pubmed:affiliation
Biozentrum of the Martin-Luther-University, Membrane Transport Group, Institute of Pharmaceutics and Biopharmaceutics, Martin-Luther-University Halle-Wittenberg, Halle, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't