Papinutti Leandro, Dimitriu Pedro, Forchiassin Flavia
Laboratorio de Micología Experimental, Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, 1428, Buenos Aires, Argentina.
Bioresour Technol. 2008 Jan;99(2):419-24. doi: 10.1016/j.biortech.2006.11.061. Epub 2007 Feb 22.
Stability of laccase isoenzymes from a crude extract obtained from Fomes sclerodermeus grown on wheat bran medium was studied. The variables assessed were temperature, pH and additives. As revealed by PAGE, three bands of laccase, each with different thermal inactivation pattern, were detected in the crude extract: after 6h at 50 degrees C and pH 8, Lc2 was the most resistant, while the Lc1 and Lc3 bands were almost completely inactivated. This pattern of inactivation was observed at all temperatures and pH tested. Laccase activity was more stable in the 5-10 pH range when incubated at 40 and 50 degrees C; at 30 degrees C and 24h the enzyme remained fully active in the 3-11 pH range. The effect of additives (veratryl alcohol, trehalose, glycerol, mannitol, glutaraldehyde, CuSO(4) and 1-HBT) on laccase stability was tested. The stability was enhanced with CuSO(4) (1.25 mM), glycerol (0.2%) and mannitol (1%). The presence of both CuSO(4) and glycerol caused a 3-fold increase in the half-life values.
对从在麦麸培养基上生长的硬皮多孔菌粗提物中获得的漆酶同工酶的稳定性进行了研究。评估的变量有温度、pH值和添加剂。通过聚丙烯酰胺凝胶电泳（PAGE）显示，在粗提物中检测到三条漆酶条带，每条具有不同的热失活模式：在50℃和pH 8条件下6小时后，Lc2最具抗性，而Lc1和Lc3条带几乎完全失活。在所有测试的温度和pH值下均观察到这种失活模式。当在40℃和50℃孵育时，漆酶活性在pH 5-10范围内更稳定；在30℃和24小时时，该酶在pH 3-11范围内仍保持完全活性。测试了添加剂（藜芦醇、海藻糖、甘油、甘露醇、戊二醛、硫酸铜和1-羟基苯并三唑）对漆酶稳定性的影响。硫酸铜（1.25 mM）、甘油（0.2%）和甘露醇（1%）可提高稳定性。硫酸铜和甘油同时存在使半衰期值增加了3倍。
