Human Kallikrein 13 Alexa Fluor™ Plus 555-conjugated Antibody

Human tissue Kallikrein 13 (hK13) is a member of the human tissue kallikrein family. The gene encoding for rhK13 is termed KLK13 and it resides on chromosome 19q13.3-4 along with fourteen other members of the family. KLK13 spans about 8.7 kb genomic DNA and the longest transcript is 831 bp, encoding for a protein of 277 amino acids (1). Another five shorter splice variants have also been identified. They are specifically expressed in the testicular tissue and encode for five truncated forms of hK13 (2). Due to the aspartic acid residue in the substrate binding pocket, the enzymatic activity of hK13 is predicted be trypsin-like. It has been shown that recombinant hK13 produced in yeast can cleave synthetic peptides after the arginine residue and some extracellular matrix components (3). However, its exact physiological substrates and functions remain obscure. Despite the lack of knowledge on the physiological function of hK13, several studies have demonstrated that hK13 is implicated with cancer of the breast and ovary and it can serve as a favorable prognostic biomarker for these malignancies (4, 5). The purified, secreted rhK13 is mainly the pro form. When activated by lysyl-endopeptidase, it displays enzymatic activity towards a fluorogenic synthetic peptide. This activity can be inhibited by rhSerpin A5, E1, and F2 (R&D Systems, Catalog # 1266-PI, 1786-PI, and 1470-PI).