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 mechanis m 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 dri ved nutrients uptake across the plasma membrane. An auto-inhibitory domain in C-terminal was identificated in the structure of this enzyme. The presen ce of the auto-inhibitory domain in vacuolar membrane proton pumps was stud ied in our experiments. The auto-inhibitory domain was identificated in ton oplast HC-ATPase (V type family), because an ATP hydrolis and H+ pumping ma rkedly increased after proteolysis. Second tonoplast proton pump, H+-pyroph osphatase, did not have this mechanism of regulations. If was concluded tha t mechanism of regulations ATPas of different families (P and V types) situ ated on different membranes had more in common, than mechanism of regulatio ns two proton pumps incrusted in to the same membrane (tonoplast H+-ATPase and H+-pyrophosphatase).