Anaerobic amino acid metabolism

Anoxic stress induces a strong change in sugar, protein and amino acid metabolism in higher plants. Sugars are rapidly consumed through the anaerobic glycolysis to sustain energy production. Protein degradation under anoxia is a mechanism to release free amino acids contributing in this way in maintaining the osmotic potential of the tissue under stress. Among free amino acids, a particular role is played by glu, being a precursor of some characteristic compounds of the anaerobic metabolism (ala, GABA and Put). The GS/GOGAT cycle contributes to ammonia re-assimilation and primary assimilation of nitrate, and re-synthesizes constantly glu for the synthesis of the other compounds. Some polypeptides involved in these pathways are expressed under anoxia. The importance of amino acid metabolism in the response to anaerobic stress will be discussed.