Human Kallikrein 8/Neuropsin Alexa Fluor™ Plus 488‑conjugated Antibody

Kallikrein 8 (KLK8), also known as neuropsin or ovasin, is a member of the human tissue kallikrein family (1). Two alternatively spliced forms exist, resulting in 260 (isoform 1) and 305 (isoform 2) amino acid sequences, respectively (2). Isoform 1 consists of a signal peptide (residues 1 to 28), a short pro peptide (residues 29 to 32) and the mature chain (residues 33 to 260). Isoform 2 is identical to isoform 1, except that a 45 amino acid segment is inserted in isoform 2 between residues 23 and 24 in isoform 1. Isoform 1 is predominantly expressed in pancreas whereas isoform 2 is preferentially expressed in adult brain and hippocampus, although both forms are expressed in fetal brain and placenta in comparable levels. The brain function of KLK8 seems evident in neuropsin knockout mice that showed abnormalities of synapses and neurons and predisposation to global seizure activity (3, 4). KLK8 is a novel marker for ovarian and cervical cancer carcinomas (5, 6). Recombinant human KLK8, after being activated by lysyl endopeptidase, can cleave fibronectin and several small peptide substrates (7, 8). This activity can be inhibited by rhSerpin A5, rhSerpin F2 and AEBSF (R&D Systems, Catalog # 1266-PI, 1470-PI and EI001, respectively). Recombinant human KLK8 produced by R&D Systems corresponds to isoform 1.