Patent ID: 8663630

Claim:
A method for reducing the concentration of hydrogen peroxide in a cell, comprising contacting said cell with a modified catalase polypeptide having a carboxy-terminal peroxisome targeting signal (PTS) that has been modified from a native sequence of Lys-Ala-Asn-Leu (SEQ ID NO:1) by replacement of SEQ ID NO:1 in catalase with a PTS comprising the sequence Xaa −3 Xaa −2 Xaa −1 , wherein, independently, Xaa −3 is Ser, Ala or Cys; Xaa −2 is Lys, Arg or His; and Xaa −1 is Leu or Met, and wherein the replacement sequence comprises, to the amino-terminal side of Xaa-3, between 3 and about 17 additional amino acid residues, wherein the modified catalase polypeptide further comprises a delivery or translocation peptide or polypeptide molecule bound thereto or associated therewith, which contacting is under conditions wherein said modified catalase polypeptide is targeted to peroxisomes in an amount sufficient to reduce said concentration.