Pavelić K, Pekić B
J Cell Physiol. 1986 Feb;126(2):307-11. doi: 10.1002/jcp.1041260222.
The electrophoretic distribution of lactate dehydrogenase (LDH) isoenzymes, Michaelis constant, reaction with substrate, and dissociation into subunits with guanidine hydrochloride was examined in undifferentiated and differentiated human myeloid leukemia cells. Differentiation was induced with 1/microgram/ml tunicamycin. Undifferentiated cells did not display phagocytic ability, and less than 5% of these cells had Fc receptors. After exposure to tunicamycin for 40 hr, 40% of these differentiated cells had Fc receptors, and 35% showed phagocytic activity after 160 hr. The majority of the LDH activity in the undifferentiated cells was found in fraction 3, and following differentiation almost a 50% reduction in LDH activity was observed in this fraction. In addition, LDH 3 isoenzyme levels were found to be greater in patients containing a high percentage of undifferentiated cells than in patients containing a high percentage of differentiated cells. Differentiated cells displayed LDH isoenzyme fraction pattern, Michaelis constant, and reaction with substrate similar to those found in the normal granulocytes. Differences in the dissociation of LDH into subunits with guanidine hydrochloride were found between undifferentiated and differentiated acute myeloid leukemia (AML) cells. Treatment with 0.75 M guanidine hydrochloride caused complete inactivation of LDH derived from normal differentiated cells, whereas similar treatment caused complete inactivation of LDH derived from AML or normal granulocytes. LDH isoenzymes derived from normal granulocytes and differentiated AML cells were also more sensitive to guanidine hydrochloride depression of fluorescence intensity. The sedimentation constant for single peak LDH at 5.5 M guanidine hydrochloride was calculated as 1.65 sec for differentiated and 1.70 sec for undifferentiated cells. The molecular weight of the polypeptide subunits for undifferentiated cells was 30,000 and for differentiated cells was 39,000. The apparent parallel between leukemic cells after induction of differentiation and normal granulocytes indicates that the leukemic cells retain their maturation potential when exposed to an inducer of differentiation.
在未分化和分化的人髓系白血病细胞中，研究了乳酸脱氢酶（LDH）同工酶的电泳分布、米氏常数、与底物的反应以及用盐酸胍解离成亚基的情况。用1/μg/ml衣霉素诱导分化。未分化细胞不显示吞噬能力，且这些细胞中不到5%具有Fc受体。暴露于衣霉素40小时后，这些分化细胞中有40%具有Fc受体，160小时后35%显示出吞噬活性。未分化细胞中的大部分LDH活性存在于第3组分中，分化后该组分中的LDH活性几乎降低了50%。此外，发现未分化细胞百分比高的患者中LDH 3同工酶水平高于分化细胞百分比高的患者。分化细胞显示出与正常粒细胞中相似的LDH同工酶组分模式、米氏常数以及与底物的反应。在未分化和分化的急性髓系白血病（AML）细胞之间，发现了用盐酸胍将LDH解离成亚基的差异。用0.75 M盐酸胍处理导致源自正常分化细胞的LDH完全失活，而类似处理导致源自AML或正常粒细胞的LDH完全失活。源自正常粒细胞和分化的AML细胞的LDH同工酶对盐酸胍降低荧光强度也更敏感。在5.5 M盐酸胍条件下，分化细胞单峰LDH的沉降常数计算为1.65秒，未分化细胞为1.70秒。未分化细胞多肽亚基的分子量为30,000，分化细胞为39,000。诱导分化后的白血病细胞与正常粒细胞之间明显的相似性表明，白血病细胞在暴露于分化诱导剂时保留了其成熟潜力。
