A material reaction that is necessary for a metabolic system and continues to supplement the consumption of systems other than the metabolic system.For example, toTricarboxylic acid cycleCoordinated operation must be accepted frequentlyAcetyl CoAOfOxaloacetic acid。But this substance and its precursorsα - ketoglutaric acidWait and actAmino acid synthesisAs the raw materials are consumed, it is necessary to supplement the oxaloacetic acid in some way.This reaction is carried out in animals by pyruvate carboxylase reaction, and in plants and bacteria byphosphoenolpyruvate carboxylaseReaction so that oxaloacetic acid can be supplemented.