Alpha naphthyl acetate esterase in human blood cells with different molecular weights

Normal human blood cells contain esterases which hydrolyze alpha-naphthyl acetate (alpha NA). Purified preparations of these cells were investigated by polyacrylamide gradient gel electrophoresis at pH 9.0 and subsequent staining of gels for esterase activity. Extractable alpha NA esterase was separated according to molecular weight. alpha NA esterase with molecular weight of 55 000 was observed only in lymphocytes and red cells. Lymphocytes from patients with B-cell chronic lymphocytic leukemia (B-CLL) showed alpha NA esterase with molecular weight of 45 000 instead of 55 000. Esterases with molecular weights of 60 000 and 70 000 were detected in granulocytes monocytes and red cells. Only platelets and red cells exhibited alpha NA esterase with molecular weight of 80 000. alpha NA esterases with molecular weight of 290 000 could be demonstrated in granulocytes and red cells. All blood cells contained esterase with molecular weight of 360 000. alpha NA esterase with molecular weight of 390 000 was detected only in red cells. In all blood cells (without lymphocytes) esterase with molecular weight of 500 000 was demonstrated. Only the enzyme in monocytes, granulocytes and red cells was sensitive to fluoride inhibition.