Linked Life Data

2166548

Source:http://linkedlifedata.com/resource/pubmed/id/2166548

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1990-9-20
pubmed:abstractText
Folate-binding proteins of three major classes have been observed in various bodily fluids and in the plasma membrane and cytoplasm of normal and neoplastic cells. A major class, the high-affinity folate-binding proteins, show a preferential and tight binding of folic acid relative to reduced folates and methotrexate and consist of water-soluble and membrane-associated forms. Soluble forms of the high-affinity binders are present in serum and milk and in the growth medium of certain cultured cell lines, whereas membrane-associated forms are observed on the surface of various cells and tissues. The binders in serum have no clearly defined function, whereas the milk binders serve to accumulate and stabilize reduced-folate compounds in milk and they may also facilitate the absorption of folates by the intestinal mucosa of neonates. Membrane-bound forms of high-affinity folate-binding proteins mediate the transport of folate compounds across plasma membranes and appear to utilize endocytosis as the transport mechanism. Membrane-associated high-affinity binding proteins contain covalently bound phospholipids and hydrophobic C-terminal amino acid sequences that are absent in the soluble forms. The remaining protein portions of these binders show considerable sequence homology. The second class is composed of folate-binding proteins that reside solely in the plasma membrane and are structurally and mechanistically distinct from the high-affinity binders. These proteins function in transport, exhibit varied substrate specificities that accommodate reduced-folate compounds with equal or higher affinity than folate, and do not utilize endocytosis as the mechanism for substrate internalization. The third class of folate-binding proteins consists of enzymes that reside in the cytoplasm of cells.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0199-9885
pubmed:author
pubmed:issnType
Print
pubmed:volume
10
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
319-35
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Folate-binding proteins.
pubmed:affiliation
Department of Molecular and Experimental Medicine, Scripps Clinic and Research Foundation, La Jolla, California 92037.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Review