Recombinant Human KLK5 protein

Kallikrein-related peptidase 5 (KLK5) is a serine protease belonging to the human tissue kallikrein family, which comprises 15 secreted enzymes (KLK1-KLK15) involved in diverse physiological processes. KLK5 is encoded by the *KLK5* gene located on chromosome 19q13.4 and is primarily expressed in epithelial tissues, including skin, breast, and prostate. It is synthesized as an inactive zymogen (pro-KLK5) and activated through proteolytic cleavage, enabling its enzymatic function. KLK5 exhibits trypsin-like activity, cleaving substrates after arginine or lysine residues, and plays critical roles in skin desquamation, inflammation, and cancer progression.

In the epidermis, KLK5 is a key regulator of the "epidermal differentiation cascade," contributing to the shedding of corneocytes by degrading cell adhesion proteins like desmoglein-1. Dysregulation of KLK5 is implicated in pathological conditions such as Netherton syndrome, a severe genetic skin disorder caused by mutations in the *SPINK5* gene, leading to uncontrolled KLK5 activity and impaired skin barrier function. Additionally, KLK5 overexpression has been linked to cancer, including breast, ovarian, and prostate cancers, where it promotes tumor invasion by processing extracellular matrix components and activating signaling pathways.

Recombinant KLK5 protein is produced using expression systems (e.g., mammalian cells, bacteria) to study its biochemical properties, substrate specificity, and interactions with inhibitors. It serves as a tool for drug discovery, particularly in developing protease inhibitors for inflammatory skin diseases or cancer therapeutics. Structural studies of recombinant KLK5 have revealed insights into its catalytic mechanism and regulatory loops, aiding the design of targeted therapies. Its role in disease pathways and therapeutic potential continue to drive research in dermatology and oncology.