Room temperature electron spin resonance (ESR) spectroscopy, together with enzyme activity measurements, have been used to study the liposome-mediated enrichment of human red blood cells with superoxide dismutase. The ESR technique was found to be useful not only for qualitative and quantitative determinations, but also for demonstration of enzyme activity inside intact cells. The molecular properties of superoxide dismutase in relation to pharmacological and biotechnological applications are reviewed.
