Isoenzyme studies in human leukemia -- II. Carboxylic esterase (E.C. 3.1.1.1.).

Isoelectric focusing analysis of esterase activity (E.C. 3.1.1.1.) has been carried out on polyacrylamide gel slabs of a variety of immunologically defined acute leukemia subtypes. Distinct isoenzyme bands and isoenzyme groups have been identified and characterized biochemically with regard to their features for substrate specificity, pH optimum and inhibition experiments. The esterase isoenzyme patterns permitted the distinction between acute myeloid and non-myeloid leukemias. Acute lymphocytic leukemias localized by their immunological profile along the T-cell axis exhibited a readily recognizable isoenzyme group (T group). Reproducible differences in isoenzyme patterns were observed in childhood common ALL which indicate that the immunologically determined entity cALL displays a clear heterogeneity with respect to biochemical profiles of enzyme markers. These results suggest that further combined biochemical and immunological characterization may significantly contribute to a better understanding of lymphopoietic and leukemic cell differentiation.