[Stable isotopes of Mg2+ as activators of the suppressed ATP-generating function of mitochondria].
The ATP-generating activity of rat myocardial mitochondria and intramitochondrial creatine kinase was examined as a function of the isotopy of the incubation medium magnesium pool. The study was performed using in vitro systems prepared from the hearts of animals injected with 1-methylnicotine amide, which suppresses the NAD (NADP)-dependent reactions in vivo. It was shown that the presence of the 25Mg paramagnetic cations essential by compensates for the intramitochondrial ATP deficiency caused by the 1-methyl-nicotine amide-induced blockade of oxidative phosphorylation. This effect is hardey achievable in systems where the magnesium pool consists of isotopes with a zero nuclear spin (24Mg, 26Mg). The restoration of mitochondrial ATP synthesis involves the participation of creatine kinase since the activity of the latter does not depend on 1-methyl-nicotine amide. In this case, the high efficiency of this restaration seems to be a spin-selective phenomenon which requires predominantly 25Mg2+ cations. A possible meaning of the data for further studies on the mechanisms of enzymatic catalysis regulation is discussed.
Kuznetsov
D A
DA
Arkhantel'skiĭ
S E
SE
Berdieva
A G
AG
Markarian
A A
AA
Khasigov
P Z
PZ
Gatagonova
T M
TM
Ktsova
S A
SA
Orlova
M A
MA
D000255:Adenosine Triphosphate / Q000096:biosynthesis*; D000818:Animals; D003402:Creatine Kinase / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D008929:Mitochondria, Heart / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR
D009243:NAD; D000255:Adenosine Triphosphate; D003402:Creatine Kinase; D008274:Magnesium