The Effects of Mg++, Ca++, Na+ and K+, on the ATPase Activity of Mitochondrial Fraction Isolated from Bovine Extraocular Muscle and Ciliary Process

ABSTRACT

The author investigated the effect of Mg++, Ca++, Na+ and K+ on the ATPase activity of mitochondrial fraction isolated from bovine extraocular muscles and ciliary processes and obtained the following results: 1. The mitochondrial fraction isolated from bovine extrocoular muscle and ciliary process appeared to possess the Na+ & K+ activated ATPase in the presence of Mg++, and on the contrary, in the absence of Mg++, the ATPase was not activated by K+, Na+ and Ca++. 2. The ATPase activity was enhanced with the increase of protein concentration in fractions from both, the bovine extraocular muscle and the ciliary process. 3. The ATPase in those fractions was potently activated under the condition of that the sample was modulated at 10 mM of K+ and 100 mM of Na+, respectively. 4. The K+- and Na+-activated ATPase in the presence of Mg++ was stimulated to enhance its activity by the addition of Ca++ up to 5 micro M, thoughby the higher concentration of Ca++ up to 10 micro M, its activity did not correspondingly increase.