Effects of vitamin E deficiency on the activities of lipid-requiring enzymes in rabbit liver and muscle.
The effects of vitamin E deficiency on membrane integrity were studied by examining the temperature dependence of membrane-bound enzyme activities in liver mitochondria and microsome and in muscle sarcoplasmic reticulum. In vitamin E-deficient rabbits, the specific activities at 37 degrees of mitochondrial oligomycin-sensitive ATPase (EC 3.6.1.3), beta-hydroxybutyrate dehydrogenase (EC 1.1.1.30), and microsomal glucose-6-phosphatase (EC 3.1.3.9) were increased, whereas those of microsomal NADH cytochrome C reductase (EC 1.6.99.3) and sarcoplasmic reticulum Ca-ATPase were reduced in comparison to control rabbits. Arrhenius plots of activity against temperature yielded a linear plot over the range 10 to 40 degrees in the case of beta-hydroxybutyrate dehydrogenase, NADH cytochrome C reductase and Ca-ATPase, and multiple discontinuities for glucose-6-phosphatase and oligomycin-sensitive ATPase. In control rabbits, all five enzymes showed a single discontinuity in the Arrhenius plot over the range 16 to 19 degrees. These results reflect changes in the microenvironment of membrane-bound enzymes as a consequence of vitamin E depletion.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D003579:Cytochrome Reductases / Q000378:metabolism; D003574:Cytochrome c Group; D004789:Enzyme Activation; D005952:Glucose-6-Phosphatase / Q000378:metabolism; D006884:Hydroxybutyrate Dehydrogenase / Q000378:metabolism; D007425:Intracellular Membranes / Q000201:enzymology; D050356:Lipid Metabolism; D008099:Liver / Q000201:enzymology*; D008862:Microsomes, Liver / Q000201:enzymology; D008930:Mitochondria, Liver / Q000201:enzymology; D009132:Muscles / Q000201:enzymology*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D013816:Thermodynamics; D014811:Vitamin E Deficiency / Q000201:enzymology*
D003574:Cytochrome c Group; D006884:Hydroxybutyrate Dehydrogenase; D003579:Cytochrome Reductases; D005952:Glucose-6-Phosphatase; D000251:Adenosine Triphosphatases