Influence of Mg2+-ions on the properties of rat heart mitochondria in dependence on the preparation.
1. The preparation of rat heart mitochondria with Potter-Elvehjem homogenizer results in mitochondria showing stimualtion of respiration induced by Mg2+. This stimualtion is neither caused by adherent hexokinase nor by energy-dependent magnesium accumulation (Mg2+ content in the presence of 10 mM glutamate: 22 nmoles/mg protein; in the presence of glutamate plus antimycin A 21 nmoles/mg protein). 2. The effect of added magnesium is excluded by addition of carboxyatractyloside. This demonstrates the activity of an ATPase outside of the mitochondrial inner membrane. 3. A simple and rapid method for the preparation of Mg2+-insensitive rat heart mitochondria is presented. The minced heart is pressed through a normal syringe and then treated with trypsin. 4. A comparison of mitochondria of both preparations shows that there is no difference in magnesium content and no energy-dependent magnesium influx.
D000263:Adenylate Kinase / Q000378:metabolism; D000818:Animals; D005260:Female; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects*; D051381:Rats
D000263:Adenylate Kinase; D008274:Magnesium