A pharmaceutical composition for in vivo administration to enhance the mobilization of Hematopoietic Stem Cells (HSCs) from bone marrow to peripheral blood, comprising a TAT-HOXB4H protein having amino acid sequence of SEQ ID NO:4, wherein the TAT-HOXB4H protein is produced by a method 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 solution by: (i) applying the solution to a HisTrap column; (ii) washing the HisTrap column; (iii) eluting the partially purified protein from the HisTrap column to form a partially purified protein solution; (iv) applying the partially purified protein solution to a MonoSP column; (v) washing the MonoSP column; (vi) eluting the purified protein from the MonoSP column in denatured form; (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 protein and hydrophobic compounds, wherein the hydrophobic compounds are capable of protecting the TAT-HOXB4H protein from forming insoluble aggregates during the denaturing salt-removing step; (ii) desalting the solution of protein and hydrophobic compounds to obtain a desalted protein and hydrophobic compound solution; (iii) removing the hydrophobic compounds from the desalted protein solution using ultrafiltration by a centricon tube or a stir-cell; and (f) storing the purified protein in IMDM medium or DMEM medium. (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 solution by: (i) applying the solution to a HisTrap column; (ii) washing the HisTrap column; (iii) eluting the partially purified protein from the HisTrap column to form a partially purified protein solution; (iv) applying the partially purified protein solution to a MonoSP column; (v) washing the MonoSP column; (vi) eluting the purified protein from the MonoSP column in denatured form; (i) applying the solution to a HisTrap column; (ii) washing the HisTrap column; (iii) eluting the partially purified protein from the HisTrap column to form a partially purified protein solution; (iv) applying the partially purified protein solution to a MonoSP column; (v) washing the MonoSP column; (vi) eluting the purified protein from the MonoSP column in denatured form; (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 protein and hydrophobic compounds, wherein the hydrophobic compounds are capable of protecting the TAT-HOXB4H protein from forming insoluble aggregates during the denaturing salt-removing step; (ii) desalting the solution of protein and hydrophobic compounds to obtain a desalted protein and hydrophobic compound solution; (iii) removing the hydrophobic compounds from the desalted protein solution using ultrafiltration by a centricon tube or a stir-cell; and (i) combining the eluted denatured protein and a solution of hydrophobic compounds to form a solution of protein and hydrophobic compounds, wherein the hydrophobic compounds are capable of protecting the TAT-HOXB4H protein from forming insoluble aggregates during the denaturing salt-removing step; (ii) desalting the solution of protein and hydrophobic compounds to obtain a desalted protein and hydrophobic compound solution; (iii) removing the hydrophobic compounds from the desalted protein solution using ultrafiltration by a centricon tube or a stir-cell; and (f) storing the purified protein in IMDM medium or DMEM medium.