Magnetic isotope effect of magnesium in phosphoglycerate kinase phosphorylation.
Phosphoglycerate kinase (PGK) is found to be controlled by a (25)Mg(2+)-related magnetic isotope effect. Mg(2+) nuclear spin selectivity manifests itself in PGK-directed ADP phosphorylation, which has been clearly proven by comparison of ATP synthesis rates estimated in reaction mixtures with different Mg isotopy parameters. Both pure (25)Mg(2+) (nuclear spin 5/2, magnetic moment +0.85) and (24)Mg(2+) (spinless, nonmagnetic nucleus) species as well as their mixtures were used in experiments. In the presence of (25)Mg(2+), ATP production is 2.6 times higher compared with the yield of ATP reached in (24)Mg(2+)-containing PGK-based catalytic systems. The chemical mechanism of this phenomenon is discussed. A key element of the mechanism proposed is a nonradical pair formation in which (25)Mg(+) radical cation and phosphate oxyradical are involved.
Buchachenko
Anatoly L
AL
N. N. Semenov Institute for Chemical Physics, Russian Academy of Sciences, Kosygin Street 4, Moscow 119991, Russia. spinchem@chph.ras.ru
Kouznetsov
Dmitri A
DA
Orlova
Marina A
MA
Markarian
Artyom A
AA
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000818:Animals; D066298:In Vitro Techniques; D007554:Isotopes; D007700:Kinetics; D008274:Magnesium / Q000737:chemistry*; D008280:Magnetics; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000201:enzymology; D010735:Phosphoglycerate Kinase / Q000737:chemistry* / Q000378:metabolism*; D010766:Phosphorylation; D013552:Swine
D007554:Isotopes; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D010735:Phosphoglycerate Kinase; D008274:Magnesium