Two antiviral proteins from leaves of Chenopodium album L, have been purifi
ed and their characteristics compared. Both of these impart resistance in h
ypersensitive hosts: against tobacco mosaic virus in Nicotiana tabacum cv.
Samsun NN and N. glutinosa, and sunnhemp rosette virus in Cyamopsis tetrago
noloba. One of them exhibited a single polypeptide with a molecular mass of
25 kD, and the other one is a complex showing polypeptide bands of 27, 25
and 18kD on SDS-PAGE. The 25 kD protein and the complex protein inhibited m
ore than 90 % lesion formation at a concentration of 20-22 mu g mL(-1). Bot
h of the proteins are basic in nature and can tolerate high temperature (up
to 90 degrees C).