TRANSAMINASE REACTION-RATES, TRANSPORT ACTIVITIES AND TCA CYCLE ANALYSIS BY POST-STEADY STATE C-13 NMR

In this work, we present the post-steady state analysis of the TCA cyc le and a closed form solution to the rate of label washout from the C4 carbon of glutamic acid through the transaminases and the malate-aspa rtate shuttle and then through alpha-ketoglutarate dehydrogenase. We d emonstrate using a model of this problem that the rate of label washou t depends not only on the flux through alpha-ketoglutarate dehydrogena se, but most importantly on the activity of the malate-aspartate shutt le as determined by the forward and reverse fluxes through the transam inases and by the rate of transport of glutamate and alpha-ketoglutara te across the mitochondrial membrane.