Membrane metallo-endopeptidase-like 1 (MMEL1, also known as Neprilysin 2) is a metalloprotease involved in sperm function and neuropeptide degradation [, ]. The expression of MMEL1 is limited to the testis and CNS []. In humans, it is involved in beta-amyloid (Abeta) degradation and hence associated with Alzheimer's disease [].