Elastase Activity in Natto, and Its Relation to Nattokinase.

In commercially obtained natto, 12 kinds of cereal and okara-natto preparations, both elastase and nattokinase activities were found. Particularly, in the natto preparations fermented with broad beans, soybeans, or green beans showed much stronger elastase activity, and it was also confirmed in Bacillus natto cells after ultrasonication. Using the commercially obtained nattokinase and natto extract, elastase activity in the eluate of isoelectricfocussing was parallel to that of nattokinase activity. Highly purified natto-elastase was proved to be identical to nattokinase by pI (about 8.7, isoelectric focussing), molecular weight (about 20, 000, gel filtration), and also by NH2-terminal amino acid sequence (21 residues) identified by Edmans method.