Stability studies of pectin methylesterase from green bell pepper (Capsicum annuum)
Castro, S.M.; Van Loey, A.; Saraiva, J.; Smout, C.; Hendrickx, M.
Communications in Agricultural and Applied Biological Sciences 69(2): 65-68
2004
ISSN/ISBN: 1379-1176 PMID: 15560189 Document Number: 577205
The thermal stability of pectin methylesterase (PME) isolated from green bell pepper (C. annuum) was determined at pH 5.6 and 7.5. The optimum pH of purified PME activity was 7.5. At natural conditions of pepper (pH 5.6), the activity of the enzyme was only 45% of the optimum value. At pH 5.6, two inactivation phases in the higher temperature range were observed, the first being at 5-57 degrees C and the second at 64 degrees C. Thermal inactivation of purified PME at both pH exhibited a biphasic inactivation behaviour. The thermostable PME fraction contributed to about 57.1+or-4% and 55.4+or-2.3% of the enzyme activity at pH 7.5 and 5.6, respectively. At pH 7.5, the heat labile stable fraction started to be inactivated at 58-60 degrees C, whereas at pH 5.6, the temperature inactivation was higher than 64 degrees C.