Pyruvate kinase isoenzymes in chromatin extracts of Ehrlich ascites tumour, Morris hepatoma 7777 and normal mouse and rat livers.
A pyruvate kinase (EC 2.7.1.40) variant inhibited by L-cysteine has been found in Ehrlich ascites tumour and Morris hepatoma 7777, but not in normal mouse and rat livers used for comparison. Chromatin extracts of all materials studied contained three pyruvate kinase isoenzymes (alpha, beta, gamma) which showed the greatest electrophoretic mobility in normal mouse and rat livers. The isoenzyme mobility diminished in both tumour chromatin extracts, and the slow migrating gamma isoenzyme exhibited sensitivity to L-cysteine inhibition. This gamma isoenzyme sensitive to L-cysteine might be considered as a tumour marker. All tumour pyruvate kinase isoenzymes were insensitive to normal signal molecules, i.e., to ATP and fructose 1,6-diphosphate, which regulate liver pyruvate kinase activity. It was, however, noted that the binding of pyruvate kinase isoenzymes to DNA is connected with a diminution in their catalytic activity.
Gumińska
M
M
Institute of Medical Biochemistry, Copernicus Academy of Medicine, Kraków, Poland.
Stachurska
M B
MB
Ignacak
J
J
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000201:enzymology*; D002843:Chromatin / Q000201:enzymology*; D003600:Cytosol / Q000201:enzymology; D007527:Isoenzymes / Q000302:isolation & purification*; D008099:Liver / Q000201:enzymology*; D008114:Liver Neoplasms, Experimental / Q000201:enzymology*; D051379:Mice; D008811:Mice, Inbred DBA; D011770:Pyruvate Kinase / Q000302:isolation & purification*; D051381:Rats
D002843:Chromatin; D007527:Isoenzymes; D011770:Pyruvate Kinase