Abstract:

In order to screen a protease suitable for producing heme-enriched polypeptides, the effects of various proteases on hydrolysis efficiency of porcine hemoglobin were compared. Under the optimal pH and temperature of proteases such as AS1398 neutral protease, 2709 alkaline protease, papain and trypsin, orthogonal experiments were used to explore the effects of enzyme type, enzyme concentration, substrate concentration and hydrolysis time on the hydrolysis degree of porcine hemoglobin and the contents of polypeptides and heme. Results showed that the effects of enzyme type and hydrolysis time on the degree of hydrolysis reached an extremely significant level (P ＜ 0.01). Substrate concentration was the most important factor to affect the content of polypeptide production. The effect of enzyme type on heme content reached a significant level (P＜ 0.05). Neutral protease is beneficial for the increase of hydrolysis degree and papain is good for the increase of polypeptide content, while alkali protease is helpful for the increase of heme content.

Key words: porcine hemoglobin, proteases, polypeptide, heme, screening