Inosine 5′-phosphate dehydrogenase activity in normal and leukemic blood cells |
| |
Authors: | Dr H J Becher G W Löhr |
| |
Institution: | (1) Department of Medicine, University of Freiburg, Germany |
| |
Abstract: | Summary The enzyme inosinic acid dehydrogenase (EC 1.2.1. 14]) was measured and partially purified (10- to 15-fold) from normal and leukemic leukocytes. From the normal blood cells, the highest activities could be detected in lymphocytes and bone marrow cells. Dependent on the blast cell count, the leukemic IMP dehydrogenase had a higher mean specific activity than the enzymes of fractionated, immature bone marrow cells, or normal granulocytes. The partially purified enzymes from the various blood cells were apparently identical; they exhibited hyperbolic substrate saturation kinetics and were inhibited by a number of purine nucleotides. For the leukemic blast cell enzyme, theK
m values for the substrates, IMP and NAD+, were 28±11; 227±98 µM, and 34±10; 240±67 µM for the partially purified enzyme from normal, immature bone marrow cells.The hypoxanthine-guanine and adenine phosphoribosyltransferase activities increased in the leukemic cells when compared with mature granulocytes, but nearly always showed similar activities when compared with the fractionated bone marrow cells. Only one of the 30 investigated leukemic patients exhibited a marked decrease in hypoxanthine phosphoribosyltransferase activity of 0.5 nmol/mg/h. The phosphoribosyltransferase-specific activities of the leukemic cells are more variable than for the normal ones and no correlation of enzyme activities and blast cell count was apparent. Abbreviations A-PRT
adenine phosphoribosyltransferase
- HG-PRT
hypoxanthine-guanine phosphoribosyltransferase
- PRPP
5-phosphoribosyl-1-pyrophosphate
- ALL
acute lymphocytic leukemia
- AML
acute myelogenous leukemia
- CLL
chronic lymphatic leukemia
- CML
chronic myelogenous leukemia
- AMMOL
acute myelomonocytic leukemia
This study was supported by the Deutsche forschungsgemeinschaft Be 458/4 |
| |
Keywords: | IMP dehydrogenase Leukemic blasts Fractionated bone marrow cells Purine salvage pathway |
本文献已被 SpringerLink 等数据库收录! |
|