Linked Life Data

2760547

Source:http://linkedlifedata.com/resource/pubmed/id/2760547

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1989-9-15
pubmed:abstractText
The aim of the present study was to characterize the acyl-coenzyme A: cholesterol acyltransferase (ACAT) activity in human liver microsomes. Liver biopsies were obtained from patients undergoing elective cholecystectomy under highly standardized conditions. In 34 patients the enzyme activity of the microsomal fraction averaged 6.6 +/- 0.7 (mean +/- SEM) pmol.min-1.mg protein-1 in the absence of exogenous cholesterol. Freezing of the liver biopsy in liquid nitrogen increased the enzyme activity five- to sixfold. Similarly, freezing of the microsomal fraction prepared from unfrozen liver tissue increased the enzyme activity about twofold. These results may help to explain previous disparate results reported in the literature. The enhanced ACAT activity obtained by freezing was at least partly explained by a transfer of unesterified cholesterol to the microsomal fraction and possibly also by making the substrate(s) more available to the enzyme. Preincubation of the microsomal fraction, prepared from unfrozen liver tissue, with unlabeled cholesterol increased the enzyme activity about fivefold. This finding indicates that hepatic ACAT in humans can also utilize exogenous cholesterol as substrate. Addition of cholesterol to frozen microsomes prepared from unfrozen liver tissue increased the ACAT activity two- to threefold, whereas addition of cholesterol to microsomes prepared from frozen liver tissue did not further increase the enzyme activity. No evidence supporting the concept that ACAT is activated-inactivated by phosphorylation-dephosphorylation could be obtained by assaying the enzyme under conditions similar to those during which the human HMG-CoA reductase is inactivated-activated.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0022-2275
pubmed:author
pubmed:issnType
Print
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
739-46
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Studies on acyl-coenzyme A: cholesterol acyltransferase activity in human liver microsomes.
pubmed:affiliation
Department of Medicine, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't