PRSS12 is a member of the trypsin family of serine proteases. Studies in mouse suggest that the encoded enzyme may be involved in structural reorganizations associated with learning and memory. The enzyme is also expressed in Leydig cells in the testis. Proba et al. (1998) cloned PRSS12 from a human fetal brain cDNA library, using primers based on a conserved region of the mouse homolog cloned by Gschwend et al. (1997). The PRSS12 cDNA encodes a deduced 875-amino acid protein that shares 82.5% overall sequence identity with the mouse protein. Human PRSS12 contains a putative signal peptide, a kringle domain, 4 repeated scavenger receptor cysteine-rich (SRCR) regions, and a C-terminal serine protease domain. Comparison of PRSS12 with other proteases identified it as a trypsin-like serine protease.