Plasma catalase

Study of plasma catalase activity on an individual basis has been limited in scope. For 50 adults the range was found to be from 4.2 to 9.5 per ml. of plasma. 19 One of the normal individuals was studied for five days, and the following values were obtained 9.5, 8.5, 9.5, 7.0, 9.5. Further study is required before one could conclude definitely that there are significant inter-individual differences. The available evidence points in that direction. In various anemias the values may be 50 or more. In one "diagnostic problem case" the value was 42. It seems highly probable that "normal" differences have physiological significance. 

Overproduction of free radicals by erythrocytes and leukocytes and iron overload result in a sharp increase in free radical damage in T1 patients. Thus, Livrea et al. [385] found a twofold increase in the levels of conjugated dienes, MDA, and protein carbonyls with respect to control in serum from 42 (3-thalassemic patients. Simultaneously, there was a decrease in the content of antioxidant vitamins C (44%) and E (42%). It was suggested that the iron-induced liver damage in thalassemia may play a major role in the depletion of antioxidant vitamins. Plasma thiobarbituric acid-reactive substances (TBARS) and conjugated dienes were elevated in (3-thalassemic children compared to controls together with compensatory increase in SOD activity [386]. The development of lipid peroxidation in thalassemic erythrocytes probably depends on a decrease in reduced glutathione level and decreased catalase activity [387]. 

The antibody-dependent lysis of tumor cells by PMNs exhibited some of the characteristics of damage mediated by products of the burst in the presence of tumor cells there was increased consumption of O2, increased formation of O and activation of the hexose monosphosphate shunt However, although a reduction in the concentration of O2 in the medium inhibited lysis neither catalase nor superoxide dismutase inhibited. The lack of effect on these enzymes was attributed to their inability to interpose themselves between the plasma membranes of the PMN and its target. Similar conclusions were reached by Clark, and Klebanoff whose data incriminated the products of the burst by the reduced killing of tumor cells by PMNs from patients with chronic granulomatous disease. Myeloperoxidase, however, appeared not to he required since neither azide or cyanide inhibited and killing by PMNs from patients with inherited deficiency of myeloperoxidase was normal. 

Zini, A., de Lamirande, E., and Gagnon, C. 1993. Reactive oxygen species in semen of infertile patients Levels of superoxide dismutase and catalase-like activities in seminal plasma and spermatozoa. Int. J. Androl. 16, 183-188. 

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