Purification and characterization of a novel fibrinolytic enzyme from chive (Allium tuberosum)

Abstract

A novel Allium tuberosum fibrinolytic enzyme (ATFE) was purified from the leaf of chive by ion exchange chromatography followed by gel filtration. The molecular mass and iso-electric point (pI) of ATFE were 90 kDa and 4.0 by using 1- or 2-D fibrin zymography, respectively. ATFE was optimally active at pH 4.0 and 40°C. ATFE had a high degrading activity for the Aα-chain of human fibrinogen and hydrolyzed the Bβ-chain slowly, but did not affect the γ-chain, indicating that it is a α-fibrinogenase. The proteolytic activity of ATFE was inhibited completely by phenylmethylsulfonyl fluoride (PMSF), indicating that this enzyme belongs to the serine protease class. ATFE was also inhibited by the 1 mM of Cu2+. ATFE exhibited high specificity for Meo-Suc-Arg-Pro-Tyr-pNA (S-2586), a synthetic chromogenic substrate for chymotrypsin. The first 20 amino acid residues of the N-terminal sequence of ATFE were determined as TTKSWNFIGFDETSKXTTYE, which is 60% identical with subtilisin-like serine protease from Narcissus pseudonarcissus. Keywords Allium tuberosum -fibrinolytic enzyme-fibrin zymography-subtilisin-like