Identification of auto-inhibitory domain in tonoplast H+-ATPase

There were two proton pumps, generated a proton-motive force: H+-ATPase and H+-pyrophosphatase, in tonoplast which drived nutrients into vacuole. The regulation of the activity of these enzymes were studied but exact mechanism of acting was unknown. The mechanism of regulation of plasma membrane H+-ATPase was more investigated. This H+-ATPase belonged to the P type family of cationtranslocating pumps and generated the proton-motive force that drived nutrients uptake across the plasma membrane. An auto-inhibitory domain in C-terminal was identificated in the structure of this enzyme. The presence of the auto-inhibitory domain in vacuolar membrane proton pumps was studied in our experiments. The auto-inhibitory domain was identificated in tonoplast HC-ATPase (V type family), because an ATP hydrolis and H+ pumping markedly increased after proteolysis. Second tonoplast proton pump, H+-pyrophosphatase, did not have this mechanism of regulations. If was concluded that mechanism of regulations ATPas of different families (P and V types) situated on different membranes had more in common, than mechanism of regulations two proton pumps incrusted in to the same membrane (tonoplast H+-ATPase and H+-pyrophosphatase).