Identity, release, and binding of mitochondrial-bound hexokinases in mammary glands and adenocarcinomas of lactating mice.
The mitochondrial-bound hexokinases (adenosine triphosphate:D-hexose 6-phosphotransferase) of mammary adenocarcinoma and of normal gland were compared in lactating C3H mice. Treatment of mitochondria isolated from both the normal and neoplastic tissue with 0.5 m NaCl or 0.1 mM glucose 0-phosphate effected the release of about 50% of the bound hexokinase. In the presence of magnesium ion, enzyme from either source attached to mitochondria from either tissue and in all combinations to the same extent. Identification of the isoenzyme complement in the mitochondrial extract by diethylaminoethylcellulose chromatography revealed only types I and II. In the tumor, the hexokinase activity in both the cytosol and the fraction solubilized from mitochondria was predominantly in the form of type I ( 60%). In contrast, the activity released from mitochondria isolated from normal gland was predominately type II, while the cytosol contained almost equivalent amounts of types I and II. While this difference does not explain differences in glucose utilization between the normal and neoplastic tissue, it may provide a means of distinguishing between the two.
D000818:Animals; D002848:Chromatography, DEAE-Cellulose; D003600:Cytosol / Q000201:enzymology; D005260:Female; D006593:Hexokinase / Q000378:metabolism*; D007527:Isoenzymes / Q000302:isolation & purification; D007774:Lactation; D008274:Magnesium / Q000494:pharmacology; D008321:Mammary Glands, Animal / Q000201:enzymology*; D008325:Mammary Neoplasms, Experimental / Q000201:enzymology*; D051379:Mice; D008809:Mice, Inbred C3H; D008928:Mitochondria / Q000201:enzymology*; D011247:Pregnancy
D007527:Isoenzymes; D006593:Hexokinase; D008274:Magnesium