Studies on Lotus Seed Protease

Some physicochemical and enzymic properties of the purified lotus seed protease were investigated. The molecular weight determined from sedimentation-diffusion studies and by Sephadex G-100 gel-filtration was 36,800 and 35,500, respectively. The enzyme gave a typical ultraviolet spectrum of protein and its isoelectric point was found to be in a range of pH 3~4. The enzyme was stabilized at pH 6 in Tris-hydrochloric acid buffer by the addition of cupric ion. The inhibitory function of some reagents, especially that of potassium permanganate, and acetylation of the enzyme revealed that the tyosine residue in this enzyme protein might play some important role in the enzyme activity. Lotus seed protease was found to be fairly similar to pepsin in some properties.