title: In Vitro Selection of Cathepsin E-Activity-Enhancing Peptide Aptamers at Neutral pH.
abstract: The aspartic protease cathepsin E has been shown to induce apoptosis in cancer cells under physiological conditions. Therefore, cathepsin E-activity-enhancing peptides functioning in the physiological pH range are valuable potential cancer therapeutic candidates. Here, we have used a general in vitro selection method (evolutionary rapid panning analysis system (eRAPANSY)), based on inverse substrate-function link (SF-link) selection to successfully identify cathepsin E-activity-enhancing peptide aptamers at neutral pH. A successive enrichment of peptide activators was attained in the course of selection. One such peptide activated cathepsin E up to 260%, had a high affinity (K(D); ∼300 nM), and had physiological activity as demonstrated by its apoptosis-inducing reaction in cancerous cells. This method is expected to be widely applicable for the identification of protease-activity-enhancing peptide aptamers.
authors.affiliation: Department of Functional Materials Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama 338-8570, Japan.
authors.forename: Madhu
authors.initials: M
authors.lastname: Biyani
authors.forename: Masae
authors.initials: M
authors.lastname: Futakami
authors.forename: Koichiro
authors.initials: K
authors.lastname: Kitamura
authors.forename: Tomoyo
authors.initials: T
authors.lastname: Kawakubo
authors.forename: Miho
authors.initials: M
authors.lastname: Suzuki
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Koichi
authors.initials: K
authors.lastname: Nishigaki