Increased activity of a basic LDH 5-related isoenzyme in cells derived from chronic myeloid leukemia.
The LDH isoenzyme pattern in cells derived from patients (n = 24) with chronic myeloid leukemia (CML) was studied using a high resolution isoelectric focusing (IEF) technique. In K562 cells a highly basic (band B, IEP greater than 10.5) LDH isoenzyme was detected. Using a 2-dimensional technique combining electrophoresis and IEF, its relation to the LDH 5 isoenzyme was demonstrated. From its heat-stability it is concluded that band B is composed of 4 M subunits. The activity of the basic band correlated with the number of CML blast cells and was absent in juvenile, band and segmented neutrophils. Our observations are compatible with a gradual loss of activity during myeloid differentiation. The nature of band B remains unclear, but artefacts due to ligand (lactate, pyruvate, NAD+) binding were ruled out.
Medizinische Universitätsklinik, Tübingen, F.R.G.
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D002454:Cell Differentiation; D006358:Hot Temperature; D006801:Humans; D007525:Isoelectric Focusing; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000032:analysis*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000201:enzymology*; D014407:Tumor Cells, Cultured
D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase