Abstract
Effect of ammonium sulfate on respiration was examined with the isolated rat liver mitochondrial system using pyruvate as substrate.
A minute amount of ammonium sulfate caused a severe inhibition of respiration, and a decreased utilization of the substrate was observed at the same time. On the other hand, glutamate and aspartate productions after the ammonium sulfate addition were too small to explain the respiratory inhibition.
The formation of α-ketoglutarate was inhibited by ammonium sulfate and the degree of the inhibition was closely related to a decrease in intramitochondrial pyridine nucleotide level. On the other hand, glutamate was largely produced by glutamate dehydrogenase reaction when α-ketoglutarate was added externally to the mitochondrial system or when flow rate of the TCA cycle was increased. In summary, ammonium sulfate inhibits respiration, while it is utilized as a nutrient for the glutamate synthesis under some different conditions.
