Putative aminopeptidase which plays a role in oocyte maturation. Binds 1 zinc ion per subunit. RNAi-mediated knockdown causes an expansion of the pachytene zone in the gonads of 31 percent of animals and a delay in oocyte nucleolus disassembly. Brood size is normal and embryos are viable. Belongs to the peptidase M1 family.