title: A thermostable trypsin inhibitor with antiproliferative activity from small pinto beans.
abstract: Small pinto bean is a cultivar of Phaseolus vulgaris. It produces a 16-kDa trypsin inhibitor that could be purified using anion exchange and size chromatography. Q-Sepharose, Mono Q and Superdex 75 columns were employed for the isolation process. Small pinto bean trypsin inhibitor demonstrated moderate pH stability (pH 2-10) and marked heat stability, with its trypsin inhibitory activity largely retained after exposure to 100 °C for half an hour. The activity was abolished in the presence of dithiothreitol, in a dose-dependent manner, implying that disulfide bonds in small pinto bean trypsin inhibitor are crucial for the activity. The trypsin inhibitor showed a blocked N-terminus. The trypsin inhibitor only slightly inhibited the viability of breast cancer MCF7 and hepatoma HepG2 cells at 125 μM.
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories , Hong Kong , China and.
authors.forename: Yau Sang
authors.initials: YS
authors.lastname: Chan
authors.forename: Yanbo
authors.initials: Y
authors.lastname: Zhang
authors.forename: Stephen Cho Wing
authors.initials: SC
authors.lastname: Sze
authors.forename: Tzi Bun
authors.initials: TB
authors.lastname: Ng
mesh_terms: D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D056945:Hep G2 Cells; D006801:Humans; D061986:MCF-7 Cells; D027805:Phaseolus / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013696:Temperature; D014357:Trypsin / Q000378:metabolism*; D014361:Trypsin Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D014361:Trypsin Inhibitors; D014357:Trypsin
keywords: Bowman--Birk; Phaseolus vulgaris; dithiothreitol; leguminous