Ion motive ATPases. I. Ubiquity, properties, and significance to cell function

ATPases involved in ion translocation are present in a diverse variety of biological membranes. Three major classes of these ‘ion motive’ enzymes, designated here as ‘P’ (phosphorylated), ‘V’ (vacuolar), and ‘F’ (F0F1), are now known to exist. In addition to the regulation of intracellular ionic or pH balance, some ATPases help drive numerous physiological or biological processes by ‘energy coupling’. Among these are muscle relaxation, receptor recycling, hormone storage, food digestion and ATP synthesis. A number of laboratories are now trying to identify individual steps of ATPase reaction pathways, while others are endeavouring to identify those ‘genetic codes’ responsible for the energy coupling events.