[ATP-metabolizing enzymes in suspensions of isolated coupled rat brain mitochondria].
An improved method for the isolation of rat brain mitochondria is described. The preparation exhibits a respiratory control index (RCI) of 6 or 7.3 in the presence of pyruvate and malate or glutamate and malate, respectively. RCI decreases to 2.5 in the presence of Mg++. When the phosphorylation of extramitochondrially added or formed ADP is suppressed by carboxyatractyloside (CAT) inhibition of the adenine nucleotide translocator, the remaining respiration amounts to 6 nmol O2/min X mg mitochondrial protein. These results and the ratio of 16 to 19 from the quotient of phosphorylating active-state respiration to CAT inhibited respiration refer to a high degree of mitochondrial coupling of respiration. Therefore the remaining respiration in the presence of Mg++ is due to a phosphokinase activity located outside the inner membrane of intact mitochondria or at nonphosphorylating mitochondrial fragments. The following activities were observed: Oligomycin sensitive ATPase, 47 mU/mg protein; hexokinase, 272 mU/mg protein; creatinphosphokinase, 116 mU/mg protein; and a surprisingly low activity of adenylatekinase, 57 mU/mg protein.
Wustmann
C
C
Institut für Pharmakologie und Toxikologie, Medizinische Akademie, Carl Gustav Carus, Dresden, DDR.
Petzold
D
D
Fischer
H D
HD
Kunz
W
W
D000249:Adenosine Monophosphate / Q000502:physiology; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000263:Adenylate Kinase / Q000378:metabolism; D000818:Animals; D001278:Atractyloside / Q000031:analogs & derivatives / Q000494:pharmacology; D001562:Benzimidazoles / Q000494:pharmacology; D001921:Brain / Q000166:cytology* / Q000201:enzymology; D001923:Brain Chemistry; D003402:Creatine Kinase / Q000378:metabolism; D006593:Hexokinase / Q000378:metabolism; D008274:Magnesium / Q000502:physiology; D008297:Male; D008928:Mitochondria / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D013379:Substrate Specificity; D014475:Uncoupling Agents / Q000494:pharmacology*
D001562:Benzimidazoles; D014475:Uncoupling Agents; D001278:Atractyloside; C005817:4,5,6,7-tetrachloro-2-trifluoromethylbenzimidazole; D000249:Adenosine Monophosphate; D000255:Adenosine Triphosphate; D006593:Hexokinase; D003402:Creatine Kinase; D000263:Adenylate Kinase; D008274:Magnesium; C003853:carboxyatractyloside
ATP-umsetzende Enzyme in Suspensionen isolierter, gekoppelter Rattenhirnmitochondrien.