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

Journal Article · Sun May 15 00:00:00 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), Vol. 263:14
• Country of Publication: United States
• Language: English

Related Subjects

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