Effect of bicarbonate buffer on the activity of cytoplasmic and mitochondrial alanine aminotransferase.

1. Bicarbonate stimulates the activity of rat brain cytoplasmic and mitochondrial alanine aminotransferase (EC 2.6.1.2) probably due to the enhanced affinity for its substrates. 2. Under the same conditions, the activity of crystalline aspartate aminotransferase was inhibited. 3. The role of bicarbonate buffer in regulation of alanine aminotransferase activity and synthesis of alanine are discussed.