期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：1994
卷号：40
期号：6
页码：593-601
DOI：10.3177/jnsv.40.593
出版社：Center for Academic Publications Japan
摘要：The inhibitory specificity and stability of ovomucoid from Japanese quail egg white (OMJPQ) were examined to understand its nutritional significance. OMJPQ showed strong inhibitory activities toward trypsins from various origins including human, and the trypsin inhibitions occurred at molar ratios of enzyme to inhibitor between 1/1 and 2/1. On the other hand, an equimolar mixture of the second and third domains of OMJPQ inhibited bovine trypsin more strongly than the corresponding native OMJPQ did. This distinction was partly explained by the presence of steric hindrance on the formation of a 2:1 trypsin-OMJPQ complex. OMJPQ retained about 100% of its original activity over a pH range from 1 to 12 after a 24-h incubation at 37°C. The inhibitor was most thermostable between pH 2 and 5, where more than 70% of its original activity was maintained after a 1-h incubation at 100°C and about 25% of the activity even after a 30-min incubation at 121°C. OMJPQ was also considerably resistant to pepsin attack. Pepsin digestion of the protein resulted in only about 40% loss of the original trypsin-inhibitory activity even after a 24-h digestion. Furthermore, the addition of bovine serum albumin to the digestion mixture brought about rapid elevation in the trypsin-inhibitory activity during an initial 30-min digestion. SDS-PAGE and immunoblot suggested that this was due to the liberation of active inhibitory domains from the native molecule by inter-domain proteolysis.
