Plasminogen Activation by Lactic Acid Bacteria

Abstract

Plasminogen was incubated with lactic acid bacteria and the plasmin activity in the mixture was measured. Three of 15 strains tested revealed significant plasminogen activation ability. Lactococcus lactis subsp. lactis biovar diacetylactis NIAI C59 showed the highest activity. The strain activated not only human plasminogen but also bovine plasminogen. The activity demonstrated a high level of thermal stability within a range of pH 3.0–9.0. The plasminogen activator activity in strain C59 increased after 15 h of cultivation, and reached a plateau after 21 h. A remarkable amount of activity was transferred to the solution when C59 cells were incubated in buffer solutions at pH 9.0 and above.