Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
50
pubmed:dateCreated
1996-10-22
pubmed:abstractText
This paper provides unambiguous evidence that brush border membrane vesicles (BBMV) routinely prepared from rabbit small intestine contain a protein that catalyzes the absorption of long-chain cholesteryl ester and ether. The protein is located on the lumenal side of the brush border membrane. The experiments demonstrate that cholesteryl oleate need not be hydrolyzed prior to its incorporation in the BBMV. Unexpectedly and surprisingly, the absorption kinetics of free and esterified cholesterol are very similar in small intestinal BBMV using mixed bile salt micelles and small unilamellar phospholipid vesicles as the donor. The water-soluble form of the protein responsible for this effect is released into the supernatant, probably by autoproteolysis, and catalyzes the exchange of both free and esterified cholesterol between two populations of small unilamellar phospholipid vesicles (SUV). The water-soluble form of the protein was partially purified by a two-step procedure involving gel filtration on Sephadex G-75 and anion-exchange chromatography on Mono Q, yielding a 50-fold increase in the specific activity of the protein. The resulting protein gave two bands on sodium dodecyl sulfate--10% polyacrylamide gel electrophoresis and was used to raise polyclonal antibodies in sheep. The IgG fraction of the sheep antisera blocked the cholesteryl oleate and cholesterol exchange between two populations of SUV mediated by the antigen. The same IgG fraction produced a partial inhibition of cholesterol absorption in small intestinal BBMV. We conclude from the data presented that, contrary to the general belief prevailing in the field of lipid digestion and absorption, long-chain cholesteryl esters may be taken up by the brush border membrane as such and need not be hydrolyzed prior to absorption. The actual contribution of this mechanism to the total absorption of long-chain cholesteryl esters is probably limited by the low solubility of these compounds in mixed bile salt micelles and lipid vesicles.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
16473-82
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Cholesteryl ester absorption by small intestinal brush border membrane is protein-mediated.
pubmed:affiliation
Laboratorium für Biochemie, Eidgenössische Technische Hochschule Zürich, ETH-Zentrum, Zürich, Switzerland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't