Patent ID: 8124377

Claim:
A method of producing and purifying a TAT-HOXB4H protein having the amino acid sequence of SEQ ID NO: 4 comprising: (a) providing a host cell comprising a vector encoding the protein; (b) expressing the protein in the host cell; (c) collecting an impure solution of the expressed protein; (d) purifying the protein from the impure solution by: (1) applying the impure solution to a chromatography column for purifying histidine-tagged proteins; (2) washing the chromatography column for purifying histidine-tagged proteins with a washing buffer; (3) eluting the protein from the chromatography column for purifying histidine-tagged proteins with an eluting buffer to form a partially purified protein solution; (4) applying the partially purified protein solution to a cation ion exchange chromatography column; (5) washing the cation ion exchange chromatography column with a washing buffer; and (6) eluting the purified protein from the cation ion exchange chromatography column in denatured form with an eluting buffer; (e) refolding the eluted denatured protein using hydrophobic compounds by: (i) combining the eluted denatured protein and a solution of hydrophobic compounds to form a solution of the protein and hydrophobic compounds; (2) desalting the solution of the protein and hydrophobic compounds to obtain a desalted protein and hydrophobic compound solution; (3) removing the hydrophobic compounds from the desalted protein and hydrophobic compound solution using ultrafiltration by a centrifugal filter tube or a stir-cell; and (f) storing the purified protein in Dulbecco's modified eagle medium (DMEM).