The present invention discloses a process for the preparation of rhPTH (1-34) also known as teriparatide by construction of a novel nucleotide, as anfragemt as set forth in SEQ. ID. No.:l encoding a chimeric fusion protein as set forth in... more
The present invention discloses a process for the preparation of rhPTH (1-34) also known as teriparatide by construction of a novel nucleotide, as anfragemt as set forth in SEQ. ID. No.:l encoding a chimeric fusion protein as set forth in SEQ.ID. No.:2 comprising of a fusion partrner consisting of 41 amino acids belonging toβ-galactosidase (LacZ) gene, an endopeptidase cleavage site, rhPTH (1-34) gene fragment, cloning the said nucleotide in an expression vector under the control of T7 promoter, transformingwith the said vector and expressing the chimeric fusion protein in fed batch fermentation. The present invention further discloses a low feed rate lactose induction for optimized expression of rhPTH (1-34) in Escherichia coli. The present invention also discloses an unique, novel two step orthogonal purification process for rhPTH (1-34) comprising of cation exchange chromatography optionally followed by preparative chromatography selected from HIC or RP-HPLC to yield a target protein of >= 99% purity. The present invention discloses a simple, cost-effective, environmentally benign method of producing high purity rhPTH (1-34).
Research Interests: Biology()
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Protein tyrosine phosphatases (PTPases) are potential tumor suppressor proteins which reverse the effects of protein tyrosine kinases (PTKs). We hypothesized that the induction of PTPase activity by the nutritional agent... more
Protein tyrosine phosphatases (PTPases) are potential tumor suppressor proteins which reverse the effects of protein tyrosine kinases (PTKs). We hypothesized that the induction of PTPase activity by the nutritional agent O-phospho-L-tyrosine (P-Tyr), a broad PTPase substrate, could potentially enhance total cellular PTPase activity and inhibit cell growth. In this study, we report that P-Tyr inhibited the growth of MDA-MB 468 cells in a dose-dependent fashion. P-Tyr incubation increased total cellular PTPase activity in MDA-MB 468 breast carcinoma cells. The increase of PTPase activity, as measured by a standard radioactive assay for PTPases, occurred within 10 min of P-Tyr incubation and was dependent on the concentration and time of incubation with P-Tyr. The increased PTPase activity in P-Tyr treated cells was also evident from a non-isotopic PTPase assay involving the dephosphorylation of epidermal growth factor receptor (EGFR). Epidermal growth factor (EGF)-mediated tyrosine phosphorylation of EGFR was decreased in situ in a time- and dose-dependent manner in P-Tyr-treated cells. Orthovanadate (100 microM for 4 h) inhibited this decrease, implicating the role of cellular PTPase in P-Tyr-mediated control of EGFR tyrosine phosphorylation. Further, EGFR kinase activity was found to be decreased in P-Tyr-treated cells. We conclude that P-Tyr may inhibit cell growth by decreasing cellular tyrosine phosphorylation. Both a decrease in activity of the EGFR kinase and increases in PTPase activity may have accounted for the growth inhibiting property of P-Tyr.
Research Interests: Biology, Medicine, Cell Division, Humans, Phosphorylation, and 13 moreProtein tyrosine phosphatase, Phosphotyrosine, Epidermal Growth Factor, Epidermal Growth Factor Receptor, Carcinogenesis, Protein Tyrosine Phosphatases, Tyrosine, Tyrosine Kinase, Tyrosine Phosphorylation, Dephosphorylation, Breast Neoplasms, Vanadates, and Protein tyrosine kinases
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Research Interests: Biology, Calcium, Cell Biology, Medicine, Humans, and 15 morePhosphatase, Phosphorylation, Protein tyrosine phosphatase, Phosphotyrosine, Epidermal Growth Factor, Protein Tyrosine Phosphatases, Extracellular, Tyrosine, Biochemistry and cell biology, Tyrosine Phosphorylation, Dephosphorylation, Intracellular, Breast Neoplasms, Medical biochemistry and metabolomics, and In Vitro Techniques(Phosphatase, Phosphorylation, Protein tyrosine phosphatase, Phosphotyrosine, Epidermal Growth Factor, Protein Tyrosine Phosphatases, Extracellular, Tyrosine, Biochemistry and cell biology, Tyrosine Phosphorylation, Dephosphorylation, Intracellular, Breast Neoplasms, Medical biochemistry and metabolomics, and In Vitro Techniques)
(Phosphatase, Phosphorylation, Protein tyrosine phosphatase, Phosphotyrosine, Epidermal Growth Factor, Protein Tyrosine Phosphatases, Extracellular, Tyrosine, Biochemistry and cell biology, Tyrosine Phosphorylation, Dephosphorylation, Intracellular, Breast Neoplasms, Medical biochemistry and metabolomics, and In Vitro Techniques)
Research Interests:
O-Phospho-L-tyrosine (P-Tyr), a substrate for a wide range of protein tyrosine phosphatases, inhibited growth of human renal and breast carcinoma cells. Growth was blocked in the S phase of the cell cycle. A decrease in the amount of... more
O-Phospho-L-tyrosine (P-Tyr), a substrate for a wide range of protein tyrosine phosphatases, inhibited growth of human renal and breast carcinoma cells. Growth was blocked in the S phase of the cell cycle. A decrease in the amount of cyclin proteins A and B was also observed. P-Tyr incubation led to activation of cellular protein tyrosine phosphatases resulting in the inhibition of tyrosine phosphorylation of epidermal growth factor receptor as well as of p34cdc2. P-Tyr synergistically sensitized the renal carcinoma ACHN cells to killing by the chemotherapeutic agents doxorubicin and etoposide. These growth inhibitory properties of P-Tyr in vitro suggest its possible use as an anticancer agent.