Isolation and Characterization of Two Protein Isoforms with Antiviral Activity from Chenopodium album L Leaves

Two antiviral proteins (AVPs) named CAP-I and CAP-II isolated and purified from the leaves of Chenopodium album cv Pusa Bathua 1 were found to inhibit tobacco mosaic virus (TMV) and sunnhemp rosette virus (SRV) infection on their respective host plants. The molecular weight of both the AVPs was found to be 24 kD. They were devoid of carbohydrate moiety and were highly basic with pI ～10.2. However, they differed with respect to amino acid composition and N-terminal sequence. They also differed with respect to IC₅₀ values, and CAP-I was found to be 2.5 fold more effective than CAP-II in inhibiting viral infection.