scholarly journals Isolation and partial characterization of canine epidermal growth factor/urogastrone

1985 ◽  
Vol 229 (3) ◽  
pp. 611-619 ◽  
Author(s):  
R Kobayashi ◽  
J R Reeve ◽  
J H Walsh

Canine epidermal growth factor (EGF)/urogastrone was partially purified from dog urine by fractional precipitation with (NH4)2SO4, ion-exchange chromatography with DEAE-cellulose DE-52, gel filtration with Sephadex G-50, and a second DE-52 chromatography, to yield receptor-competing activity equivalent to 13 micrograms of standard mouse EGF/litre of starting urine. The purification was monitored by a competitive radioreceptor assay using fixed monolayers of A431 cells. The partially purified canine EGF/urogastrone demonstrated a growth-stimulating activity in 3T3 mouse fibroblast cells as potent as mouse EGF. Analysis by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis revealed one major peptide component with an Mr similar to that of mouse EGF, and two minor peptides of slightly higher Mr. The major peptide component was isolated after reduction and its amino acid composition was determined.

1992 ◽  
Vol 262 (4) ◽  
pp. F639-F646 ◽  
Author(s):  
A. V. Cybulsky ◽  
P. R. Goodyer ◽  
M. D. Cyr ◽  
A. J. McTavish

Proliferation of glomerular epithelial cells (GEC) and release of prostaglandins (PG) and thromboxane (Tx) A2 may occur in glomerular injury. We studied the relationship of eicosanoids to epidermal growth factor (EGF)-induced proliferation of rat GEC in culture. After 48 h of serum-deprivation, EGF stimulated [3H]thymidine incorporation ninefold above serum-deprived cells. Inhibition of cyclooxygenase with indomethacin or of Txsynthase with OKY-046 decreased the proliferative effect of EGF by 50 and 38%, respectively. The effect of indomethacin was reversed by addition of PGE2. Synthesis of PGE2, PGF2 alpha, and TxA2 by serum-deprived GEC was not enhanced by EGF. Scatchard analysis of 125I-EGF binding to GEC demonstrated two populations of EGF receptors; the high-affinity site had a dissociation constant (Kd) of 444 pM and 24,864 receptors/cell. EGF receptor autophosphorylation (reflecting receptor activation) was studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting of GEC membrane proteins with anti-phosphotyrosine antibody. EGF increased phosphorylation of a protein of approximately 170 kDa, which comigrated with proteins immunoprecipitated from [35S]methionine-labeled GEC with antibodies to EGF receptor. Indomethacin and OKY-046 decreased the EGF-dependent phosphorylation of the 170-kDa protein, and this decrease was overcome by addition of PGE2. Indomethacin and OKY-046 did not, however, reduce 125I-EGF binding. Thus, in GEC, the basal synthesis of eicosanoids enhanced EGF-induced proliferation. This effect appears to be due to enhancement of EGF receptor activation.


Author(s):  
RIMA MELATI ◽  
ANNISA INDRIYANI ◽  
SHABARNI GAFFAR ◽  
SRIWIDODO ◽  
IMAN PERMANA MAKSUM

Objective: The objective of this study was to evaluate two signal peptides (TorA and PelB), representing the most common secretion pathways in Escherichia coli, for their ability to secrete recombinant human epidermal growth factor (rhEGF) protein in the extracellular expression. Methods: E. coli BL21 (DE3) as the host cell to be transformed using recombinant plasmid pD881-TorA the consensus already containing hEGF gene and the signal peptide TorA or PelB, then expressed by L-rhamnose induction. rhEGF purified by heat treatment and ion-exchange chromatography. The hEGF protein was characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and ELISA. Results: The result showed that PelB was secreting more hEGF protein compared to TorA with protein expression results of 48.2 μg/L and purification results of 0.360 μg/L, with a purity level of 83%. Conclusion: The results of this study explain in extracellular expression of hEGF protein in E. coli, PelB helps hEGF protein secretion to culture media better than TorA.


1983 ◽  
Vol 3 (8) ◽  
pp. 1343-1352 ◽  
Author(s):  
A R Frackelton ◽  
A H Ross ◽  
H N Eisen

Protein kinases that phosphorylate the hydroxyl group of tyrosine residues of proteins have been implicated in cell transformation by some retroviruses and in regulation of normal cell growth by some polypeptide growth factors. To facilitate the identification of tyrosine kinase substrates, we developed monoclonal antibodies to the hapten azobenzylphosphonate. One of these antibodies, MA-2G8, proved to be especially attractive in that it bound a derivative of aminophenylphosphate, a close phosphotyrosine analog, with higher affinity than it bound the corresponding derivative of aminobenzylphosphonate; however, its affinity for phosphoserine was negligible. In this paper we describe the optimal conditions for using this antibody to isolate phosphotyrosine proteins, emphasizing particularly that its interaction with phosphotyrosyl proteins is sensitive to ionic detergents and to antibody density on the immunosorbent matrix. The antibody also bound ATP citrate lyase; this enzyme lacks phosphotyrosine but contains phosphohistidine, which is similar structurally to phosphotyrosine. By attaching the antibody at high density to Sepharose beads and omitting ionic detergents from the buffers, it was possible by microbatch immunoadsorption (followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) to isolate the 120,000-dalton transforming protein and several other phosphotyrosyl proteins from cells transformed by Abelson murine leukemia virus. Under the same conditions, phosphotyrosyl proteins were also isolated from human epidermal carcinoma cells (A431) that had been stimulated with epidermal growth factor; most prominent among these proteins was the 170,000-dalton receptor for epidermal growth factor.


1989 ◽  
Vol 120 (5) ◽  
pp. 616-623 ◽  
Author(s):  
Takashi Joh ◽  
Makoto Itoh ◽  
Naoji Yasue ◽  
Tadahisa Miyamoto ◽  
Akira Iwai ◽  
...  

Abstract. Rat epidermal growth factor was purified from rat submandibular glands to obtain specific antiserum for the establishment of an immunoassay system. Purified rat epidermal growth factor showed a single peak on reverse phase HPLC and a single band on sodium dodecyl sulphate polyacrylamide gel electrophoresis at mol wt 5100 in the presence of 2-mercaptoethanol and at mol wt 41000 in the absence of 2-mercaptoethanol. Antibody against rat epidermal growth factor showed crossreactivities with mouse and human epidermal growth factors on soft agar-double immunodiffusion test. The established sandwich enzyme immunoassay for rat epidermal growth factor had a high sensitivity (500 fg/tube), which made it possible to measure minute amounts of endogenous rat epidermal growth factor without pretreatment. Physiological concentrations of rat epidermal growth factor in rat biological fluids and tissues were determined. Species differences in physiological distributions of epidermal growth factor are discussed.


1983 ◽  
Vol 3 (8) ◽  
pp. 1343-1352
Author(s):  
A R Frackelton ◽  
A H Ross ◽  
H N Eisen

Protein kinases that phosphorylate the hydroxyl group of tyrosine residues of proteins have been implicated in cell transformation by some retroviruses and in regulation of normal cell growth by some polypeptide growth factors. To facilitate the identification of tyrosine kinase substrates, we developed monoclonal antibodies to the hapten azobenzylphosphonate. One of these antibodies, MA-2G8, proved to be especially attractive in that it bound a derivative of aminophenylphosphate, a close phosphotyrosine analog, with higher affinity than it bound the corresponding derivative of aminobenzylphosphonate; however, its affinity for phosphoserine was negligible. In this paper we describe the optimal conditions for using this antibody to isolate phosphotyrosine proteins, emphasizing particularly that its interaction with phosphotyrosyl proteins is sensitive to ionic detergents and to antibody density on the immunosorbent matrix. The antibody also bound ATP citrate lyase; this enzyme lacks phosphotyrosine but contains phosphohistidine, which is similar structurally to phosphotyrosine. By attaching the antibody at high density to Sepharose beads and omitting ionic detergents from the buffers, it was possible by microbatch immunoadsorption (followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) to isolate the 120,000-dalton transforming protein and several other phosphotyrosyl proteins from cells transformed by Abelson murine leukemia virus. Under the same conditions, phosphotyrosyl proteins were also isolated from human epidermal carcinoma cells (A431) that had been stimulated with epidermal growth factor; most prominent among these proteins was the 170,000-dalton receptor for epidermal growth factor.


1990 ◽  
Vol 1052 (3) ◽  
pp. 453-460 ◽  
Author(s):  
Jos A.M. Berkers ◽  
Paul M.P. van Bergen en Henegouwen ◽  
Arie J. Verkleij ◽  
Johannes Boonstra

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