[The NMR study of succinate formation from exogenous precursors in anaerobic rat heart mitochondria].
Succinate formation during incubation of isolated rat heart mitochondria with exogenous precursors, malate, alpha-ketoglutarate, oxaloacetate and L-glutamate was studied in the absence of aeration. The formation of succinate, the end product of the tricarboxylic acid cycle, occurs via two pathways: through reduction of oxaloacetate or malate and via oxiation of alpha-ketoglutarate. The highest rate of succinate synthesis was observed when mitochondria were incubated with a mixture of 5 mM L-glutamate and 10 mM oxaloacetate, i.e., when both routes were used simultaneously. The [U-13C]succinate/succinate and aspartate/succinate ratios were equal to 2, when mitochondria were incubated with 5 mM [U-13C]glutamate and 10 mM oxaloacetate. Therefore, the amount of succinate formed from [13C]alpha-ketoglutarate via transamination of [13C]glutamate with oxaloacetate exceeds twice succinate production from oxialoacetate. These data suggest that GTP formation in the succinic thiokinase reaction should exceed twice the ATP yield coupled with NADH-dependent reduction of fumarate.
D000693:Anaerobiosis; D000818:Animals; D001219:Aspartate Aminotransferases / Q000378:metabolism; D004734:Energy Metabolism; D005971:Glutamates / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008929:Mitochondria, Heart / Q000201:enzymology / Q000378:metabolism*; D010071:Oxaloacetates / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013386:Succinates / Q000096:biosynthesis*
D005971:Glutamates; D010071:Oxaloacetates; D013386:Succinates; D001219:Aspartate Aminotransferases
Izuchenie metodom IaMR obrazovaniia suktsinata iz ékzogennykh predshestvennikov v neaériruemykh mitokhondriiakh serdtsa krysy.