3.1.3. Effect of temperature on the activity and stability of crude proteases
Optimal temperature for activity of the crude enzyme wasdetermined in order to assess their suitability for biotechno-logical applications. Fig. 3a shows the enzyme activity of thecrude extract as a function of temperature. The crude enzyme had an optimum activity around 55◦C. The relative activitiesat 50 and 60◦C were about 93% and 45%, respectively, of thatat 55◦C. The optimal temperature of S. scrofa proteases wassimilar to that of Nile tilapia (Alencar et al., 2003) and higherthan those of crude enzymes extracted from L. mormyrus (ElHadj-Ali et al., 2011), Cyprinus carpio L. (Esposito et al., 2009b),and Zosterisessor ophiocephalus (Nasri et al., 2012) which haveoptimal temperatures at 50◦C.The thermal stability profiles reported in Fig. 3b showedthat the crude enzyme is highly active (more than 90% of itsinitial activity) for at least 30 min at 30 and 40◦C, which isdesirable for laundry purposes and from the ecological andeconomical point of view, mainly, because of saving of energy.At 50◦C, the crude enzyme retained more than 60% of its initialactivity. However, it was inactivated at higher temperatures.The thermoactivity and thermostability were also exam-ined by incubating the crude enzyme in the presence of 5 mMMgSO4at different temperatures. As shown in Fig. 3, boththe activity and stability of the crude enzyme were enhancedin the presence of MgSO4. The crude enzyme retained morethan 80% of its initial activity after 30 min incubation at 50◦Cin the presence of 5 mM MgSO4; however, in the absenceof MgSO4, only 62% of initial activity was retained. Theseresults are in accordance with several works reported themajor role of metal ions in stabilization of enzymes at highertemperatures. The improvement in protease thermostability
เป็น 3.1.3. ผลของอุณหภูมิในกิจกรรมและความมั่นคงของ proteases ดิบOptimal temperature for activity of the crude enzyme wasdetermined in order to assess their suitability for biotechno-logical applications. Fig. 3a shows the enzyme activity of thecrude extract as a function of temperature. The crude enzyme had an optimum activity around 55◦C. The relative activitiesat 50 and 60◦C were about 93% and 45%, respectively, of thatat 55◦C. The optimal temperature of S. scrofa proteases wassimilar to that of Nile tilapia (Alencar et al., 2003) and higherthan those of crude enzymes extracted from L. mormyrus (ElHadj-Ali et al., 2011), Cyprinus carpio L. (Esposito et al., 2009b),and Zosterisessor ophiocephalus (Nasri et al., 2012) which haveoptimal temperatures at 50◦C.The thermal stability profiles reported in Fig. 3b showedthat the crude enzyme is highly active (more than 90% of itsinitial activity) for at least 30 min at 30 and 40◦C, which isdesirable for laundry purposes and from the ecological andeconomical point of view, mainly, because of saving of energy.At 50◦C, the crude enzyme retained more than 60% of its initialactivity. However, it was inactivated at higher temperatures.The thermoactivity and thermostability were also exam-ined by incubating the crude enzyme in the presence of 5 mMMgSO4at different temperatures. As shown in Fig. 3, boththe activity and stability of the crude enzyme were enhancedin the presence of MgSO4. The crude enzyme retained morethan 80% of its initial activity after 30 min incubation at 50◦Cin the presence of 5 mM MgSO4; however, in the absenceof MgSO4, only 62% of initial activity was retained. Theseresults are in accordance with several works reported themajor role of metal ions in stabilization of enzymes at highertemperatures. The improvement in protease thermostability
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