Alteration of beta-hexosaminidase activity and isoenzymes in human leukemic cells.
beta-Hexosaminidase (EC 3.2.1.20; Hex) activity and isoenzyme characteristics were analyzed in human normal and leukemic leukocytes. Unseparated CLL and CML cells had a specific activity that was lower, whereas ALL and AML blasts had a higher specific activity than normal lymphocytes and granulocytes. CLL B-cells had a lower specific activity compared with that in normal non-T-lymphocytes; CLL T-cells and normal T-cells had similar activity. Isoenzyme separation was performed by chromatofocusing on PBE-94 coupled with an automated enzyme assay. When using a single linear pH elution gradient, normal leukocytes and all leukemia cells contained two forms of isoenzyme (B and A). When a double pH elution gradient was performed, an extra distinct form of Hex (I) was recorded. Hex I was present in small amounts in normal granulocytes and PHA-stimulated normal lymphocytes; isoenzyme I was found in high amounts in all leukemias tested. The activity ratios I/B and I/A, as well as the I isoenzyme profile, may facilitate differentiation between normal and leukemic cells and between lymphoblastic and myeloblastic leukemias.
D001402:B-Lymphocytes / Q000201:enzymology; D002852:Chromatography, Ion Exchange; D006801:Humans; D007527:Isoenzymes / Q000097:blood*; D007938:Leukemia / Q000201:enzymology*; D007945:Leukemia, Lymphoid / Q000201:enzymology; D007951:Leukemia, Myeloid / Q000201:enzymology; D015470:Leukemia, Myeloid, Acute / Q000201:enzymology; D010835:Phytohemagglutinins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000201:enzymology; D001619:beta-N-Acetylhexosaminidases / Q000097:blood*
D007527:Isoenzymes; D010835:Phytohemagglutinins; D001619:beta-N-Acetylhexosaminidases