Thermal stability of plasminogen activators and plasminogen activation in heated milk
2007; Elsevier BV; Volume: 17; Issue: 9 Linguagem: Inglês
10.1016/j.idairyj.2007.02.001
ISSN1879-0143
AutoresB.M. Prado, Baraem Ismail, Orlando Rivera Ramos, K.D. Hayes,
Tópico(s)Protease and Inhibitor Mechanisms
ResumoThermal stabilities of bovine plasminogen (PG) activators, tissue and urokinase type (t-PA and u-PA), and their impact on activation of PG, were studied after application of various heating conditions (65, 75, 85, or 90 °C for 15, 20, or 30 s), in both milk and buffer systems. Both t-PA and u-PA were thermally stable in milk heated at ⩽75 °C. However, almost half of the t-PA activity and 30% of u-PA activity was lost after heating milk at 85 °C for 30 s. A lower heat stability of both t-PA and u-PA was observed in buffer than in milk. The decrease in level of PG was more pronounced than that of active plasmin in milk heated at ⩾85 °C for 30 s; however, the residual level of PG was considerably higher than the residual level of active PL. Overall, results indicated that u-PA plays a more significant role than t-PA in the activation of PG during storage of heated milk.
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