Cathepsin V (CTSV)

Cathepsin L2 is a member of the peptidase C1 family, is a lysosomal cysteine proteinase that may play an important role in corneal physiology. This gene is expressed in colorectal and breast carcinomas but not in normal colon, mammary gland, or peritumoral tissues, suggesting a possible role for this gene in tumor processes.

The predicted 334-amino acid protein was designated cathepsin L2 because it shared 78% sequence identity with cathepsin L. Cathepsin L2 contains a 17-amino acid signal sequence and a 96-amino acid proregion. Recombinant protein displayed cysteine proteinase activity in vitro, with substrate specificity similar to that of cathepsin L. Northern blot analysis revealed that cathepsin L2 is expressed as a 1.8-kb mRNA predominantly in thymus and testis.