A new subtilisin-like proteinase from roots of the dandelion Taraxacum officinale Webb S. L.

A serine proteinase from roots of Taraxacum officinale Webb S. L. was isola ted by affinity chromatography and gel-filtration on Superose 6R using FPLC . The enzyme is a 67-kD glycoprotein containing 54% carbohydrate which we h ave named taraxalisin. The substrate specificity of taraxalisin toward synt hetic peptides and oxidized insulin B-chain is comparable with that of cucu misin from Cucumis melo and the subtilisin-like serine proteinase maclurali sin from Maclura pomifera. The proteinase is inactivated by DFP and PMSF. T araxalisin exhibits maximal activity at pH 8.0. The pH range for stability of the enzyme is narrow-6.0-9.0. The temperature optimum for the subtilisin -like activity is 40 degrees C. The N-terminal sequence of taraxalisin has 40% of its residues identical to those of subtilisin Carlsberg. Thus, the s erine proteinase from dandelion roots is a member of the subtilisin family, which is evidently widespread in the plant kingdom.