KLK2b ht4, a head to tail cyclic peptide, is an inhibitor of human glandular kallikrein enzyme, kallikrein-2 (KLK2). This enzyme belongs to kallikreins, serine protease family, which comprises of 15 members (KLK1-KLK15). KLK2 is increased in tumor tissues and in serum of patients with prostate cancer and is considered as a biomarker for this type of cancer.
Inhibition of KLK2 activity might be a promising therapy for prostate cancer. KLK2b ht4 cyclic peptide shows higher stability and biological activity compared with linear peptide inhibitors.