Catalytic subunit of the V1 complex of vacuolar(H+)-ATPase (V-ATPase), a multisubunit enzyme composed of a peripheral complex (V1) that hydrolyzes ATP and a membrane integral complex (V0) that translocates protons (By similarity). V-ATPase is responsible for acidifying and maintaining the pH of intracellular compartments and in some cell types, is targeted to the plasma membrane, where it is responsible for acidifying the extracellular environment (By similarity). Required along with other vacuolar ATPase components for the removal of protein aggregates which form in immature oocytes in the distal gonad. This removal occurs as the oocytes mature and move to the proximal gonad, is triggered by the introduction of sperm through mating and occurs before fertilization. The introduction of sperm triggers V-ATPase accumulation in proximal oocytes and induces lysosomal acidification which leads to engulfing of protein aggregates by lysosomes and subsequent clearance of the aggregates. Lysosomal acidification also leads to changes in mitochondrial morphology and function. Mitochondria in distal immature oocytes are fragmented, produce high levels of reactive oxygen species (ROS) and have high membrane potential, indicative of metabolic inactivity. In contrast, mitochondria in proximal mature oocytes are tubular with lower ROS levels and membrane potential, indicative of an active metabolic state required for aggregate mobilization before clearance. Involved in receptor-mediated endocytosis (By similarity). ATP + 4 H(+)(in) + H2O = ADP + 5 H(+)(out) + phosphate V-ATPase is a heteromultimeric enzyme made up of two complexes: the ATP-hydrolytic V1 complex and the proton translocation V0 complex. The V1 complex consists of three catalytic AB heterodimers that form a heterohexamer, three peripheral stalks each consisting of EG heterodimers, one central rotor including subunits D and F, and the regulatory subunits C and H. The proton translocation complex V0 consists of the proton transport subunit a, a ring of proteolipid subunits c9c'', rotary subunit d, subunits e and f, and the accessory subunits vah-19/Ac45 and vah-20/PRR. Belongs to the ATPase alpha/beta chains family.