Natural plant enzyme inhibitors. Purification and properties of an amylase inhibitor from yam (Dioscorea alata)
✍ Scribed by K. Krishna Sharma; Thillaisthanam N. Pattabiraman
- Publisher
- John Wiley and Sons
- Year
- 1982
- Tongue
- English
- Weight
- 488 KB
- Volume
- 33
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
Abstract
A high‐molecular‐weight α‐amylase inhibitor has been isolated from mature tubers of Dioscorea alata by extraction with 0.02M acetate buffer (pH 5.0), negative absorption on CM‐cellulose and ultracentrifuging. The inhibitor was fairly heat stable and was active against human salivary, human pancreatic and pig pancreatic amylases. The inhibitor had no action on Bacillus subtilis and Aspergillus oryzae amylases. Trypsin and α‐chymotrypsin inactivated the inhibitor. Pre‐incubation of the inhibitor with starch or concanavalin A resulted in complete abolition of its activity. Chemical modification of the amino groups with trinitrobenzene sulphonic acid led to loss of activity. The inhibitor was found to be a glycoprotein with 64% carbohydrate. The monosaccharide units present were glucose, mannose and galactose in a molar ratio of 5.5:3.8:1.