title: Isolation and characterisation of a kallikrein-like enzyme from Agkistrodon halys pallas snake venom.
abstract: BACKGROUND
  Viper snake venoms contain a great variety of toxic proteins. These components mediate their toxicity by either stimulating or inhibiting the haemostatic system of human victims or experimental animals, resulting in common clinical complications of blood clotting or uncontrolled haemorrhage. Therefore it is deemed important to isolate the active component(s) from snake venom with kallikrein-like activity.
  
  
  RESULTS
  A kallikrein-like proteinase of Agkistrodon halys pallas snake venom, designated AHP-Ka, was purified by anion exchange chromatography and affinity chromatography. Physicochemical studies showed that the purified enzyme was a 34 kDa monomeric glycoprotein, the molecular weight of which decreased to 26 kDa after deglycosylation with peptide N-glycosidase F (PNGase F). Sequence studies on the NH(2) -terminal region of the protein indicated that AHP-Ka shared a high degree of sequence homology with other serine proteinases from snake venoms. AHP-Ka showed high catalytic activity and kallikrein-like activity on substrates such as arginine esterase BAEE and chromogenic H-D-Pro-Phe-Arg-pNA·2HCl (S-2302) and was inhibited by protease inhibitor phenylmethylsulfonyl fluoride (PMSF).
  
  
  CONCLUSIONS
  The results showed that AHP-Ka isolated from A. halys pallas snake venom and purified by anion exchange chromatography and affinity chromatography is in fact a kallikrein-like enzyme.
authors.affiliation: Laboratory of Food Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Wentao
authors.initials: W
authors.lastname: Xu
authors.forename: Biao
authors.initials: B
authors.lastname: Ma
authors.forename: Kunlun
authors.initials: K
authors.lastname: Huang
authors.forename: Menwei
authors.initials: M
authors.lastname: Song
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yunpeng
authors.initials: Y
authors.lastname: Wang
authors.forename: Yunqing
authors.initials: Y
authors.lastname: Dai
authors.forename: Yunbo
authors.initials: Y
authors.lastname: Luo
mesh_terms: D017836:Agkistrodon; D000595:Amino Acid Sequence; D000818:Animals; D003435:Crotalid Venoms / Q000737:chemistry / Q000201:enzymology* / Q000302:isolation & purification / Q000378:metabolism; D007610:Kallikreins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010664:Phenylmethylsulfonyl Fluoride / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D057057:Serine Proteases / Q000737:chemistry
chemical_list: D003435:Crotalid Venoms; D011480:Protease Inhibitors; D010664:Phenylmethylsulfonyl Fluoride; D057057:Serine Proteases; C573897:AHP-Ka, Agkistrodon halys pallas; D007610:Kallikreins