Variations in Catalase Activity in Human Leukocytes

By CHEV KIDS0N C ATALASE is an enzyme found in most body tissues which has the capacity to release molecular oxygen from hydrogen peroxide ( H202 ) . It is concerned with peroxidation of substrates such as alcohol, phenol, formate and formaldehyde.1 Catalase in blood has aroused considerable interest, the enzyme content being higher than that in other tissues except liver.2 Most studies have concemed only the erythrocyte enzyme3’4 because of earlier difficulties in separating leukocytes in sufficiently pure preparations for enzyme assay. ‘The introduction of dextran methods5 of isolation of leukocytes from erythrocytes has enabled a more careful study to he made of the leukocyte enzyme. Recently, Tomonaga et al.6 have investigated methods for studying leukocyte catalase activity, employing dextran separation followed by differential osmotic lysis of residual erythrocytes for preparing pure leukocyte samples. Applying these methods, Ichimaru7 has reported interesting alterations in the activity of this enzyme in leukemia, showing an increase in leukocyte catalase activity in chronic myeloid leukemia, very low levels in chronic lymphatic leukemia and a wide range of activities in acute leukemias. The assessment of such findings raises the problem common to all studies of quantitative alterations of leukocyte enzymes in leukemia, namely the difficulty of interpreting comparisons made with mixed normal leukocyte populations. In the present study the preparation of both granulocyte-rich and lymphocyte-rich fractions of normal whole leukocyte populations has permitted a comparison of catalase activity of leukemic leukocytes with that of the normal cell prototypes. This has also permitted the question of cell age in relation to alterations of catalase activity in myeloid leukemia to be considered on the basis of studies on young leukocyte populations in infective states.