Cytosolic fractions B (salted out between 51-70%
ammonium sulphate saturation) from rat liver and
Morris hepatoma 7777, containing
pyruvate kinase (EC 2.7.1.40) M2
isoenzymes, were purified by affinity chromatography on
Blue Sepharose CL-6B. When compared by
polyacrylamide gel electrophoresis at pH 8.3, all three M2
pyruvate kinase variants from
Morris hepatoma 7777 had lower mobilities (alpha2, beta2, gamma3) than the three corresponding variants (alpha1, beta1, gamma2) from normal rat liver. Using an automatic
amino-acid analyser, significant differences in selected
amino-acid content have been found in corresponding highly purified gamma3 and gamma2 variants from
Morris hepatoma and normal rat liver, respectively. The gamma3-variant of the
Morris hepatoma M2
isoenzyme had twice the amount of
L-tyrosine and
L-cysteine, and a content of
L-serine higher by 20% than the corresponding gamma2 variant of the normal rat liver M2
isoenzyme. It contained, however, significantly less
dicarboxylic amino acids which explains its lower electrophoretic mobility. It showed also a decrease (by about 10%) in several other
amino-acid content, corresponding to
a 10% decrease in the tumour
enzyme molecular mass.