Research Article
Ziqin Liu and Huihua Huang
Abstract
Effect of trypsin hydrolysis on lipase in activation, characteristics and change in thermal stability were studied. Lipase was found to be increased in activity from 584U mL-1 to 759U mL-1 via trypsin treatment at the concentration of 1.5mg mL-1, 30ºC and pH7.0 for 30min. The trypsin-treated lipase showed a lower Km value (79mg mL-1 olive oil substrate) than the native lipase (100mg mL-1), indicating an improved affinity for olive oil substrate. The optimum pH value of the trypsin-treated lipase maintained basically unchanged while the optimum temperature (45ºC) showed lower than the native lipase (50ºC). The half-inactivation time for the trypsin-treated lipase at 45ºC, 50ºC and 60ºC was calculated as 131min, 35.5min and 4min respectively, while for the native lipase at 50ºC and 60ºC was calculated as 128min and 13min respectively, indicating that the thermal stability of lipase is lowered after trypsin treatment.