The interconversion of glutamic acid and aspartic acid in respiring tissues

Abstract

Homogenates of rat and pigeon liver, pigeon breast muscle and sheep kidney cortex convert added glutamate into aspartate. Under some conditions, the amounts of glutamate removed and aspartate formed are approximately equal. The homogenates also convert aspartate into glutamate, the amounts formed being about 50% of the amounts of aspartate removed. In many cases, these reactions account for most of the O2 consumption in the presence of glutamate or aspartate. An almost stoichiometric conversion of glutamate into aspartate also occurs in rat-brain mitochondria. In mitochondria of rat and pigeon liver and of pigeon breast muscle, the yield of aspartate was only 20-30% of the glutamate removed. Washed suspension of Escherichia coli and Alcaligenes faecalis did not accumulate aspartate on the addition of glutamate.