Linked Life Data

3129432

Source:http://linkedlifedata.com/resource/pubmed/id/3129432

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
14
pubmed:dateCreated
1988-6-9
pubmed:abstractText
Covalent conjugation of superoxide dismutase and catalase with polyethylene glycol (PEG) increases the circulatory half-lives of these enzymes from less than 10 min to 40 h, reduces immunogenicity, and decreases sensitivity to proteolysis. Because PEG has surface active properties and can induce cell fusion, we hypothesized that PEG conjugation could enhance cell binding and association of normally membrane-impermeable enzymes. Incubation of cultured porcine aortic endothelial cells with 125I-PEG-catalase or 125I-PEG-superoxide dismutase produced a linear, concentration-dependent increase in cellular enzyme activity and radioactivity. Fluorescently labeled PEG-superoxide dismutase incubated with endothelial cells showed a vesicular localization. Mechanical injury to cell monolayers, which is known to stimulate endocytosis, further increased the uptake of fluorescent PEG-superoxide dismutase. Endothelial cell cultures incubated with PEG-superoxide dismutase and PEG-catalase for 24 h and then extensively washed were protected from the damaging effects of reactive oxygen species derived from exogenous xanthine oxidase as judged by two criteria: decreased release of intracellular 51Cr-labeled proteins and free radical-induced changes in membrane fluidity, measured by electron paramagnetic resonance spectroscopy of endothelial membrane proteins covalently labeled with 4-maleimido-2,2,6,6-tetramethylpiperidinooxyl. Addition of PEG and PEG-conjugated enzymes perturbed the spin-label binding environment, indicative of producing an increase in plasma membrane fluidity. Thus, PEG conjugation to superoxide dismutase and catalase enhances cell association of these enzymes in a manner which increases cellular enzyme activities and provides prolonged protection from partially reduced oxygen species.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
263
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6884-92
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Superoxide dismutase and catalase conjugated to polyethylene glycol increases endothelial enzyme activity and oxidant resistance.
pubmed:affiliation
Department of Anesthesiology, University of Alabama at Birmingham, University Station 35233.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't