Serine protease which exhibits a preference for Arg over Lys in the substrate P1 position and for Ser or Pro in the P2 position. Shows activity against amyloid precursor protein, myelin basic protein, gelatin, casein and extracellular matrix proteins such as fibronectin, laminin, vitronectin and collagen. Degrades alpha-synuclein and prevents its polymerization, indicating that it may be involved in the pathogenesis of Parkinson disease and other synucleinopathies. May be involved in regulation of axon outgrowth following spinal cord injury. Tumor cells treated with a neutralizing KLK6 antibody migrate less than control cells, suggesting a role in invasion and metastasis. {ECO:0000269|PubMed:11983703, ECO:0000269|PubMed:12878203, ECO:0000269|PubMed:12928483, ECO:0000269|PubMed:15557757, ECO:0000269|PubMed:16321973, ECO:0000269|PubMed:16987227}. This is the function of ENSG00000167755 (KLK6, kallikrein related peptidase 6).