Isoenzyme studies in human leukemia-lymphoma cell lines--IV. Lactate dehydrogenase.

Isoelectric focusing (IEF) in horizontal polyacrylamide gels has been used to separate lactate dehydrogenase (LDH) isoenzymes in 97 human permanent hematopoietic cell lines (85 leukemia-lymphoma cell lines and 12 'normal' B-lymphoblastoid cell lines). Maximally 8 LDH bands were seen; the electrophoretically detectable bands 4 and 5 could be separated by IEF into 2 and 3 isoenzymes, respectively. The LDH patterns have been found to vary both in number of isoenzymes and in relative intensity in different cell lines depending upon the stage at which arrest of differentiation occurred. These differences can be used to analyse and distinguish different cell lines. The method should provide a valuable supplement to the enzymatic phenotyping and complete characterization of fresh and cultured leukemias and for the monitoring of phenotypic changes occurring during induction of differentiation.