Superoxide dismutase and catalase conjugated to polyethylene glycol increases endothelial enzyme activity and oxidant resistance

Journal Article · Sun May 15 04:00:00 EDT 1988 · J. Biol. Chem.; (United States)

OSTI ID:6771901

Beckman, J S; Minor, Jr, R L; White, C W; Repine, J E; Rosen, G M; Freeman, B A

Covalent conjugation of superoxide dismutase and catalase with polyethylene glycol (PEG) increases the circulatory half-lives of these enzymes from <10 min to 40 h, reduced immunogenicity, and decreases sensitivity to proteolysis. Because PEG has surface active properties and can induce cell fusion, the authors hypothesized that PEG conjugation could enhance cell binding and association of normally membrane-impermeable enzymes. Incubation of cultured porcine aortic endothelial cells with /sup 125/I-PEG-catalase or /sup 125/I-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. 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.

• Research Organization: Univ. of Alabama, Birmingham (USA)
• OSTI ID: 6771901
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 263:14; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
ANIMAL TISSUES
AROMATICS
AZAARENES
BETA DECAY RADIOISOTOPES
BIOCHEMISTRY
BODY
CATALASE
CHEMISTRY
CHROMIUM 51
CHROMIUM ISOTOPES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELECTRON SPIN RESONANCE
ENDOTHELIUM
ENZYME ACTIVITY
ENZYMES
EVEN-ODD NUCLEI
GLYCOLS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC POLYMERS
OXIDOREDUCTASES
PEROXIDASES
POLYETHYLENE GLYCOLS
POLYMERS
PURINES
RADIOISOTOPES
RESONANCE
SUPEROXIDE DISMUTASE
TISSUES
XANTHINES