Spin biochemistry: magnetic 24Mg-25Mg-26Mg isotope effect in mitochondrial ADP phosphorylation.

The rates of adenosine triphosphate (ATP) production by isolated mitochondria and mitochondrial creatine kinase incubated in isotopically pure media containing, separately, (24)Mg(2+), (25)Mg(2+), and (26)Mg(2+) ions were shown to be strongly dependent on the magnesium nuclear spin and magnetic moment. The rate of adenosine 5'-diphosphate phosphorylation in mitochondria with magnetic nuclei (25)Mg is about twice higher than that with the spinless, nonmagnetic nuclei (24,26)Mg. When mitochondrial oxidative phosphorylation was selectively blocked by treatment with 1-methylnicotine amide, (25)Mg(2+) ions were shown to be nearly four times more active in mitochondrial ATP synthesis than (24,26)Mg(2+) ions.

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.

A novel electrophoretic technique designed to modify the ratio of magnesium isotopes inside the creatine kinase active sites. A preliminary report.

A simple and efficient preparative electrophoretic technique has been proposed to obtain a modified creatine kinase (CK, E.C.2.