Abstract: Abstract By an improved procedure, pokeweed antiviral protein (PAP-s) has been preoared from seeds of Phytolacca arnerzcona and P.acinosa respectively. Our experiment demonstrated that the characters of PAP-s from both two species were all the same. The protein is a single peptide chain with MW 30,000 and pI 8. 4 determined by SDS-PAGE and eictrofocusing on Ampholine/polycrylamide-gel plates. Edman degradation showed that N-terminal residue of PAP-s was lie. PAP-inhibits protein synthesis in a rabbit reticulocyte lysate with an ID50 of 2.6 ng/ml (8.6xl0^11 mol/l). The multiplication of poliomyclity virus type III m monkey kidney cells infected m the presence of the protein is strongly inhibited, a 98% inhibition being caused by it at a concentration of 4.17 ×lO^-8 mol/1. PAP-s has been conjugated to monoclonal antibody Wu71 to from immunotoxin specifically toxic to T-lymphocyte leukemia CEM cells.

Key words: Phytolacca acinosa