title: Purification and characterization of an anticoagulant oligopeptide from Whitmania pigra Whitman.
abstract: BACKGROUND
  Dried Whitmania pigra is used for the treatment of cardiovascular and cerebrovascular diseases in traditional Chinese medicine and hot water and alcohol extracts also have anticogulant activity. However, a lower molecular weight and more stable anticogulant is needed.
  
  
  OBJECTIVE
  The objective of the following study is to purify and characterize of an anticoagulant oligopeptide from Hirudo (Whitmania pigra Whitman).
  
  
  METHODS
  Gel filtration on Sephadex G-50, ion exchange on diethylaminoethyl-cellulose, and semi-prepared high-performance liquid chromatography were used to purify Hirudo. Automated coagulation analyzer was used for evaluating anticoagulant activity. Molecular weight was measured by Matrix-assisted laser desorption ionization time of flight mass spectrometry. Amino acid sequence of the oligopeptide was measured by amino acid sequence analyzer.
  
  
  RESULTS
  A new anticoagulant, named whitide, isolated from Hirudo was purified, with a molecular weight 1997.1 Da. Amino acid sequence of the oligopeptide was identified as Gly-Pro-ALa-Gly-Hyp-Val-Gly-Ala-Hyp-Gly-Gly-Hyp-Gly-Val-Arg-Gly-Leu-Hyp-Gly-Asp-Arg-Gly. The results revealed that its amino acid sequence had strong homology to various types of collagen.
  
  
  CONCLUSIONS
  Whitide might be an orally anticoagulant for its hot and trypsin stable.
authors.affiliation: Department of Identification and Assessment of TCM, Hubei University of Traditional Chinese Medicine, Key Laboratory of TCM Resource and TCM Compound Co-constructed by Hubei province and Ministry of Education, New products of TCM Senile Diseases Co-Innovation Center of Hubei ; Department of Quality Control, Wuhan Institute of Biological Products Co., Ltd., China.
authors.forename: Xiaobei
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Department of Identification and Assessment of TCM, Hubei University of Traditional Chinese Medicine, Key Laboratory of TCM Resource and TCM Compound Co-constructed by Hubei province and Ministry of Education, New products of TCM Senile Diseases Co-Innovation Center of Hubei.
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430065, China.
authors.forename: Zhengwang
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Identification and Assessment of TCM, Hubei University of Traditional Chinese Medicine, Key Laboratory of TCM Resource and TCM Compound Co-constructed by Hubei province and Ministry of Education, New products of TCM Senile Diseases Co-Innovation Center of Hubei.
authors.forename: Yimei
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Identification and Assessment of TCM, Hubei University of Traditional Chinese Medicine, Key Laboratory of TCM Resource and TCM Compound Co-constructed by Hubei province and Ministry of Education, New products of TCM Senile Diseases Co-Innovation Center of Hubei.
authors.forename: Keli
authors.initials: K
authors.lastname: Chen
keywords: Amino acid sequence; Whitmania pigra Whitman; anticoagulant; oligopeptide