N-Aiginine Dibasic Convertase (NRD-C) is a prohormone convertase purified and cloned from rat testis. NRD-C is classified within the zinc metalloprotease family of proteases of which other members include Pitrilysin and Insulysin. NRD-C is a MOkDa protein predominantly located within the testes but is also present at lower levels in other endocrine systems such as the cortex and adrenal glands. NRD-C functions to cleave peptide sequences on the N-terminal of an arginine residue in a pair of basic amino acids. Cleavage by NRD-C is highly specific. In order to elucidate the function of the acidic domain of NRD-C the following specific project aims are proposed: study possible protein-protein interactions within the'acidic domain using a yeast-two-hybrid approach and examine whether the acidic domain affects the cellular localisation of the enzyme using green fluorescent protein NRD-C chimeric proteins.