Kallikrein 6, also known as Zyme, Neurosin, PRSS9, myelencephalon-specific protease (MSP) and protease M, is a trypsin-like serine proteinase. Kallikrein 6 was originally described from the brain as an enzyme involved in degradation of amyloid plaque protein (APP) and hK6 was thought to be a beta secretase.
Kallikrein 6 was shown to be elevated in the sera patients with Alzheimer’s disease and Parkinson’s disease and in animal models of multiple sclerosis. The neuronal protein alpha-synuclein was shown to be cleaved by hK6, as has APP and hK6 has been implicated in vascular morphogenesis and angiogenesis. MSP has also been shown to rapidly degrade myelin-specific protein, laminin and fibronectin.