Cysteine protease activity in arils of Thaumatococcus daniellii: Relationship between the sweet protein thaumatin and cysteine protease activity

• 1.

  1. The intensely sweet protein thaumatin was originally reported to possess autolytic activity, manifest only in the presence of reducing agents. We have shown that the proteolytic activity in partially purified thaumatin preparations is attributable to a cysteine proteinase, thaumatopain, that can be separated from thaumatin by cation exchange chromatography.

• 2.

  2. Lesser peaks of proteolytic activity coeluted with thaumatin variants, which did not completely exclude the possibility of a weak but inherent proteolytic activity in the thaumatins.

• 3.

  3. The minor proteolytic peaks were resolved from thaumatins by hydrophobic interaction chromalography, and are probably due to minor charge variants of the thaumatopains. Thaumatin has no intrinsic proteolytic activity.