INACTIVATION OF GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE OF HUMAN-MALIGNANT CELLS BY METHYLGLYOXAL

The effect of methylglyoxal on the activity of glyceraldehyde-3-phosph ate dehydrogenase (GA3PD) of several normal human tissues and benign a nd malignant tumors has been tested. Methylglyoxal inactivated GA3PD o f all the malignant cells (47 samples) and the degree of inactivation was in the range of 25-90%, but it had no inhibitory effect on this en zyme from several normal cells (24 samples) and benign tumors (13 samp les). When the effect of methylglyoxal on other two dehydrogenases nam ely glucose 6-phosphate dehydrogenase (G6PD) and L-lactic dehydrogenas e (LDH) of similar cells was tested as controls it has been observed t hat methylglyoxal has some inactivating effect on G6PD of all the norm al, benign and malignant samples tested, whereas, LDH remained complet ely unaffected. These studies indicate that the inactivating effect of methylglyoxal on GA3PD specifically of the malignant cells may be a c ommon feature of all the malignant cells, and this phenomenon can be u sed as a simple and rapid device for the detection of malignancy.