Kexin () is a

prohormone A prohormone is a committed precursor of a hormone consisting of peptide hormones synthesized together that has a minimal hormonal effect by itself because of its expression-suppressing structure, often created by protein folding and binding addit ...

-processing

protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalysis, catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products ...

, specifically a yeast serine peptidase, found in the budding

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom (biology), kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are est ...

('' S. cerevisiae''). It

catalyzes Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...

the cleavage of -Lys-Arg- and -Arg-Arg- bonds to process

alpha-factor

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

and killer toxin precursors. The human homolog is PCSK4. It is a family of subtilisin-like peptidases. Even though there are a few prokaryote kexin-like peptidases, all kexins are eukaryotes. The enzyme is encoded by the yeast gene ''KEX2'', and usually referred to in the scientific community as Kex2p. It shares structural similarities with the bacterial protease

subtilisin Subtilisin is a protease (a protein-digesting enzyme) initially obtained from ''Bacillus subtilis''. Subtilisins belong to subtilases, a group of serine proteases that – like all serine proteases – initiate the nucleophilic attack on the ...

. The first mammalian homologue of this protein to be identified was furin. In the mammal, kexin-like peptidases function in creating and regulating many differing proproteins.

Nomenclature

The enzyme is also known as yeast KEX2 protease, proteinase yscF, prohormone-processing endoprotease, paired-basic endopeptidase, yeast cysteine proteinase F, paired-basic endopeptidase, andrenorphin-Gly-generating enzyme, endoproteinase Kex2p, gene KEX2 dibasic proteinase, Kex 2p proteinase, Kex2 endopeptidase, Kex2 endoprotease, Kex2 endoproteinase, Kex2 protease, proteinase Kex2p, Kex2-like precursor protein processing endoprotease, prohormone-processing KEX2 proteinase, prohormone-processing proteinase,

proprotein convertase Proprotein convertases (PPCs) are a family of proteins that activate other proteins. Many proteins are inactive when they are first synthesized, because they contain chains of amino acids that block their activity. Proprotein convertases remove tho ...

, protease KEX2, Kex2 proteinase, and Kex2-like endoproteinase.

References

External links

* EC 3.4.21 {{enzyme-stub