Characteristics of phytase in sunflower meal and broad beans

ABSTRACT

Properties of sunflower meal and cotyledon broad bean phytases were studied after extraction with 2% CaCl2 followed by ammonium sulphate partial purification. The enzyme showed an optimum pH of 4.0 and 4.2 respectively and optimum temperature of 45C for each phytases. The phytase of the tow extracts where partially inhibited at high substrate concentration, with an optimum substrate concentration at 9mM and 5mM respectively, and km value of 1.11 x 10-3M and 0.59 x 10- 3M. V max was 0.51 and 0.62 u mole P liberated/min/ml enzyme respectively. The inactivation and activation energy for the hydrolysis of phytic acid were approximately 39.700 cal/mole and 9100 cal/mole respectively of sunflower phytase, whereas these values were 40.400 ca./mole and 11.300 cal/mole of bean phytase. The percentage of sunflower enzyme inhibition were about 28%, 24%, 36% and 48% in the presence of 10-3M zinc, cupric, ferrous and mercuric respectively. Also, these salts reduced phytase activity from bean by 25%, 20%, 20% and 28%, respectively