title: Purification and Characterization of a Novel Kazal-Type Trypsin Inhibitor from the Leech of Hirudinaria manillensis.
abstract: Kazal-type serine proteinase inhibitors are found in a large number of living organisms and play crucial roles in various biological and physiological processes. Although some Kazal-type serine protease inhibitors have been identified in leeches, none has been reported from Hirudinaria manillensis, which is a medically important leech. In this study, a novel Kazal-type trypsin inhibitor was isolated from leech H. manillensis, purified and named as bdellin-HM based on the sequence similarity with bdellin-KL and bdellin B-3. Structural analysis revealed that bdellin-HM was a 17,432.8 Da protein and comprised of 149 amino acid residues with six cysteines forming three intra-molecular disulfide bonds. Bdellin-HM showed similarity with the Kazal-type domain and may belong to the group of "non-classical" Kazal inhibitors according to its Cys(I)-Cys(II) disulfide bridge position. Bdellin-HM had no inhibitory effect on elastase, chymotrypsin, kallikrein, Factor (F) XIIa, FXIa, FXa, thrombin and plasmin, but it showed a potent ability to inhibit trypsin with an inhibition constant (Ki) of (8.12 ± 0.18) × 10(-9) M. These results suggest that bdellin-HM from the leech of H. manillensis plays a potent and specific inhibitory role towards trypsin.
authors.affiliation: Department of Endocrine and breast Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China. yanmay_lai@163.com.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Lai
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences &amp; Yunnan Province, Kunming Institute of Zoology, Kunming 650223, China. lbw19901006@126.com.
authors.forename: Bowen
authors.initials: B
authors.lastname: Li
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences &amp; Yunnan Province, Kunming Institute of Zoology, Kunming 650223, China. liuweihui00@126.com.
authors.forename: Weihui
authors.initials: W
authors.lastname: Liu
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences &amp; Yunnan Province, Kunming Institute of Zoology, Kunming 650223, China. wang.gan@outlook.com.
authors.forename: Gan
authors.initials: G
authors.lastname: Wang
authors.affiliation: Life Sciences College, Nanjing Agricultural University, Nanjing 210095, China. ducw1992@163.com.
authors.forename: Canwei
authors.initials: C
authors.lastname: Du
authors.affiliation: Sino-Africa Joint Research Center, Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming 650223, Yunnan, China. roseombati@gmail.com.|Institute of Primate Research, P.O Box 24481, Nairobi, Kenya. roseombati@gmail.com.
authors.forename: Rose
authors.initials: R
authors.lastname: Ombati
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences &amp; Yunnan Province, Kunming Institute of Zoology, Kunming 650223, China. rlai@mail.kiz.ac.cn.|Sino-Africa Joint Research Center, Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming 650223, Yunnan, China. rlai@mail.kiz.ac.cn.
authors.forename: Ren
authors.initials: R
authors.lastname: Lai
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences &amp; Yunnan Province, Kunming Institute of Zoology, Kunming 650223, China. longchb@163.com.
authors.forename: Chengbo
authors.initials: C
authors.lastname: Long
authors.affiliation: Department of Endocrine and breast Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China. hongy_li@hotmail.com.
authors.forename: Hongyuan
authors.initials: H
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D007865:Leeches / Q000737:chemistry*; D008970:Molecular Weight; D009930:Organic Chemicals / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D000072417:Protein Domains; D013329:Structure-Activity Relationship; D014357:Trypsin / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D009930:Organic Chemicals; D014361:Trypsin Inhibitors; C107927:bdellin; D014357:Trypsin
keywords: Hirudinaria manillensis; Kazal-type trypsin inhibitor; bdellin; protease inhibitor