A modified form of mitochondrial hexokinase produced by ATP-induced solubilization

Mitochondrial hexokinases from several rat tissues were analyzed by DEAE-cellulose chromatography. Solubilization by glucose-6-P or Triton X-100 released hexokinases A and B. Solubilization by ATP resulted in a decrease of hexokinase A and the concomitant appearance of a new fraction of lower net charge (hexokinase Am) which readily reverts to hexokinase A by dialysis or dilution. Treatment of homogeneous or partially purified hexokinase A with ATP did not generate hexokinase Am. Hexokinases Am and A were equally inhibited by an anti-hexokinase immune serum and displayed the same Km values for glucose and ATP. Hexokinase Am may represent a conformer or an oligomer produced during ATP-induced solubilization of hexokinase A from mitochondria.