hGH AND METHODS FOR PREPARING hGH
Preparations of recombinant human growth hormone (hGH) are provided having a purity that comprises 2% or less of a peptide other than native human growth hormone (e.g., essentially free of multimeric forms) are disclosed. Active pharmaceutical ingredient (API) preparations of recombinant hGH suitable for commercial production of formulation grade recombinant hGH are provided. A stable Master Cell Bank of transformed E. coli is also disclosed, as well as methods for creating a transformed E. coli preparation that includes a Met-AsphGH encoding sequence. Improved manufacturing methods are also presented that are suitable for large scale production of highly purified preparations of recombinant human growth hormone.
1 . A method for preparing a composition comprising a recombinant human growth hormone preparation, said recombinant human growth hormone preparation having 2% or less of other than a peptide having an amino acid sequence of native recombinant human growth hormone, said method comprising the steps of:
preparing a vector comprising a nucleic acid sequence encoding native human growth hormone having a dipeptide met-asp appended to the N-terminus to provide a transformation vector;
transforming an E. coli with said transformation vector to provide a transformed E. coli;
inducing the transformed E. coli to transcribe the hGH-dipeptide met-asp sequence;
harvesting the induced transformed E. coli and collecting an enriched population of transformed E. coli comprising inclusion bodies;
solubilizing said inclusion bodies in a high urea preparation and collecting metasphGH;
refolding the metasphGH in the presence of a phosphate buffer by dialysis against a phosphate buffer solution;
cleaving the Met Asp-hGH to provide a recombinant hGH preparation;
processing said recombinant hGH preparation over an ion exchange chromatography column and collecting ion exchanged hGH pooled fractions;
subjecting the ion exchanged hGH pooled fraction to reverse phase chromatography to provide a RPHPLC pool; and
processing the RPHPLC pool to provide to provide a purified recombinant hGH.
2 . The method of claim 1 wherein the processing of the RPHPLC pool comprises adjusting, desalting; and lyophilizing the RPHPLC pool to provide a purified recombinant hGH.
3 . The method of claim 1 wherein the ion exchange chromatography step is conducted in the absence of acetonitrile.
4 . The method of claim 1 wherein the E. coli is a BL21.
5 . The method of claim 1 wherein cleaving the MetAsp-hGH is performed in the presence of an appropriate ratio of cathepsin C.
6 . The method of claim 1 wherein the peptide having an amino acid sequence other than native human growth hormone is desamidated hGH.
7 . The method of claim 1 wherein the recombinant human growth hormone is essentially free of dimer and multimer hGH species.
8 . The method of claim 1 wherein the transformation vector is pTrcHis2A/kan-MDN hGH.
9 . A recombinant human growth hormone preparation having 2% or less of a desamidated form of hGH as determined by reverse phase HPLC chromatogram.
10 . The recombinant human growth hormone preparation of claim 8 comprising 1% or less of a desamidated form of hGH as determined by reverse phase HPLC chromatogram.
11 . The recombinant human growth hormone preparation of claim 9 essentially free of a desamidated form of hGH as determined by reverse phase HPLC chromatogram.
12 . Recombinant human growth hormone produced by a method which comprises:
culturing E. coli cells which contain a recombinant DNA molecule, which DNA molecule comprises a nucleotide sequence encoding human growth hormone preceded by a methionine-asparagine residue at its N-terminus, said encoding nucleotide sequence contained in an expression system effective in producing said encoded human growth hormone in said E. coli cells; and
recovering the human growth hormone from the culture.
13 . The human growth hormone of claim 9 which is in purified and isolated form.
14 . An active pharmaceutical ingredient (API) of recombinant human growth hormone isolated from a recombinant E. coli transformed with the transformation vector of FIG. 18 .
15 . The active pharmaceutical ingredient (API) of claim 14 formulated as an injectable preparation.
16 . A transformed recombinant E. coli comprising a plasmid pTrcHis2A/kan-metasphGH.
17 . The recombinant E. coli of claim 16 wherein the E. coli is a BL21 E. coli.
18 . A Master Cell Bank comprising the transformed recombinant E. coli of claim 16 .
19 . A recombinant plasmid pTrcHis2A/KANNhGH as depicted in FIG. 18 .