Stoichiometric traps in the tricarboxylic acid cycle. I. Self-inhibition and triggering phenomena.

摘要: The steady-state oxidation of 2 mM pyruvate in pigeon and rat heart mitochondria the presence ADP-glucose-hexokinase load can be strongly inhibited by excess (10-40 mM) or beta-hydroxybutyrate. This inhibition is accompanied accumulation alpha-ketoglutarate a decrease malate. mechanism such substrate may associated with limitation tricarboxylic acid cycle flux low levels oxaloacetate free CoA due to their being trapped as acetyl-CoA. Contrary pyruvate, ketone bodies absence other substrates produce self-inhibition at concentrations 0.5-1 mM. At 10-15 acetoacetate, complete suppression respiration develop. high (preset ADP uncoupler CCCP), characterised malate alpha-ketoglutarate. loads, reverse distribution intermediates takes place. It concluded that system body an example biochemical triggers (systems two alternative stable states).