Kallikrein-related peptidase 5 (KLK5), formerly known as stratum corneum tryptic enzyme (SCTE), is a serine protease

Serine protease

Serine proteases are enzymes that cleave peptide bonds in proteins, in which serine serves as the nucleophilic amino acid at the active site.They are found ubiquitously in both eukaryotes and prokaryotes...

 expressed in the epidermis

Epidermis

Epidermis may refer to:* Epidermis , in plants, the outermost layer of cells covering the leaves and young parts of a plant* Epidermis , the outermost layer of the skin of a human...

. In humans it is encoded by the KLK5 gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

. This gene is one of the fifteen kallikrein subfamily members located in a cluster on chromosome 19. Its expression is up-regulated by estrogens and progestins. Alternative splicing results in multiple transcript variants encoding the same protein.

KLK5 has been suggested to regulate cell shedding (desquamation

Desquamation

Desquamation , also called skin peeling, is the shedding of the outermost membrane or layer of a tissue, such as the skin.-Skin:Normal, nonpathologic desquamation of the skin occurs when keratinocytes, after moving apically over about 14 days, are individually shed unnoticeably...

) in conjunction with KLK7

KLK7

Kallikrein-related peptidase 7 is a serine protease that in humans is encoded by the KLK7 gene. KLK7 was initially purified from the epidermis and characterised as stratum corneum chymotryptic enzyme...

 and KLK14

KLK14

Kallikrein-14 is a protein that in humans is encoded by the KLK14 gene.-External Links:* The MEROPS online database for peptidases and their inhibitors:...

, given its ability to degrade proteins which form the extracellular component of cell junctions in the stratum corneum

Stratum corneum

The stratum corneum is the outermost layer of the epidermis, consisting of dead cells that lack nuclei and organelles. The purpose of the stratum corneum is to form a barrier to protect underlying tissue from infection, dehydration, chemicals and mechanical stress...

. It is proposed that KLK5 regulates this process since it is able to self-activate in addition to activating KLK7 and KLK14.

External Links

• The MEROPS
  Merops
  Merops may refer to:* Merops , a genus of bee-eaters.* MEROPS, an on-line database for peptidases.It may also refer to several figures from Greek mythology:* King of Ethiopia, husband of Clymene, who lay with Helios and bore Phaethon...
  
  online database for peptidases and their inhibitors: S01.017