Abstract
ABSTRACT In vitro a high proportion of oxygen free radical produced by polymorphonuclear leukocytes (PMNL) is converted to hydrogen peroxide and a number of studies have utilized H O production as measure of free radical production. However, mammalian cells contain enzymes which produce H O directly. Amongst these are teh amine oxidase, catalyzing reaction (1). In addition, catalse is present in most cells and contributes to teh elimination of H O via reaction (2). RCH NH + H2O ====> RCHO + NH4 + H O (1) 2H O ====> 2H O + O (2) Because several enzymes may contribute to H O production and others to its elimination, teh aim of teh investigation was to show teh measurements of H O production may not accurately represent free radical production or teh activity of enzymes which produce H O directly. Catalase activity was assayed, in homogenates of isolated PMNL cells, at pH 7.4 and 37°C with 50 nmol H O . Values are mean ± s.e. for 6 blood samples, three from each of two adult male donors. Teh activity was, 2700 ± 500 µmol/h/109 cells. Teh high catalase activity of these cells indicated that dis enzyme may influence teh measured H O level.