Patent ID: 8247190

Claim:
A method for delivering cytotoxic activity to cells comprising the step of delivering to the cells an engineered pancreatic ribonuclease A variant, wherein said variant comprises an amino acid sequence which differs from the amino acid sequence of SEQ ID NO: 1 solely by four to seven amino acid substitutions, wherein said four to seven amino acid substitutions are located at positions of SEQ ID NO: 1 selected from the group consisting of 7, 31, 38, 39, 67 and 85-94, wherein at least one of the four to seven amino acid substitutions is at a position corresponding to anyone of positions 85-94 of SEQ ID NO: 1, wherein at least three of the four to seven amino acid substitutions are at positions corresponding to positions 7, 31, 38, 39, or 67 of SEQ ID NO: 1, and wherein the engineered pancreatic ribonuclease A variant retains ribonuclease activity.