The energy charge of the adenylate system or adenylate energy charge (AEC) has been defined by Atkinson and Walton (1967) as (ATP + ½ ADP)/(AMP + ADP + ATP). Wheather the AEC is a fundamental metabolic control parameter remains a controversial topic.
Reference: Atkinson 1967 J Biol Chem
MitoPedia concepts: MiP concept
MitoPedia topics: Substrate and metabolite