Further increase in enzyme concentration increased the deproteinization degree (70 ± 1.1% using 1 U/mg; 78 ± 0.8% using 5 U/mg),and beyond 10 U/mg the deproteinization degree remained constant (80 ± 1.1% and 80 ± 1.5% for 10 and 15 U/mg,respectively)