leupeptins and ferrous-chloride

Chives have been used both as food and as medicine. Previously, two fibrinolytic enzymes, ATFE-I (90 kDa) and ATFE-II (55 kDa), were identified in chives (Allium tuberosum), a perennial herb. In the present work, ATFE-II was purified by ion-exchange chromatography followed by gel filtration. In addition, the enzyme properties of ATFE-I and ATFE-II were compared. The molecular mass and isoelectric point (pI value) of ATFE-II were 55 kDa and pI 4.0, respectively, as revealed using one- or two-dimensional fibrin zymography. ATFE-II was optimally active at pH 7.0 and 45°C. ATFE-II degraded the Aα-chain of human fibrinogen but did not hydrolyze the Bβ-chain or the γ-chain, indicating that the enzyme is an α-fibrinogenase. The proteolytic activity of ATFE-II was completely inhibited by 1 mM leupeptin, indicating that the enzyme belongs to the cysteine protease class. ATFE-II was also inhibited by 1 mM Fe²(+). ATFE-II exhibited high specificity for MeO-Suc-Arg-Pro-Tyr-p-nitroaniline (S-2586), a synthetic chromogenic substrate of chymotrypsin. Thus proteolytic enzymes from A. tuberosum may be useful as thrombolytic agents.

Topics: Chive; Cysteine Endopeptidases; Cysteine Proteinase Inhibitors; Drug Discovery; Ferrous Compounds; Fibrinogen; Fibrinolysis; Fibrinolytic Agents; Hydrogen-Ion Concentration; Hydrolysis; Isoelectric Point; Isoenzymes; Leupeptins; Molecular Weight; Oligopeptides; Plant Components, Aerial; Plant Proteins; Substrate Specificity; Temperature; Thrombolytic Therapy; Thrombosis