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enzyme activities of normal human blood cells were measured, and isoelectric focusing patterns of
acid esterase (AcE) (EC 3.1.1.6) and
acid phosphatase (AcP) (EC 3.1.3.2) were compared with corresponding data obtained for two acute T-
lymphoblastic leukemia cell lines (JM, Molt-4), one acute B-
lymphoblastic leukemia cell line (Ball-1), one acute non-B-non-T-
lymphoblastic leukemia cell line (KM 3), and one promyelocytic
leukemia cell line (HL-60). The AcE
isozymes, found in the individual blood cell types, were regularly expressed by the corresponding cell lines. AcP was regularly expressed by lines HL-60 and KM 3, but lines JM, Molt-4, and Ball-1 showed additional
isozymes and/or reduction of the intensity of the typical
isozymes found in the presumed normal counterparts. This phenomenon resulted partly in an obscuration of the typical
isozyme patterns. Our study documents the applicability of
isozyme mapping to the characterization of permanent hematopoietic cell lines. The results suggest that long-term culture conditions can repress phenotypic properties and/or derepress gene activities.