scholarly journals Electrochemical detection of aquatic humic substances based on anodic dissolution of a copper electrode in high-performance size-exclusion chromatography.

1991 ◽  
Vol 7 (1) ◽  
pp. 165-167
Author(s):  
Naoyoshi EGASHIRA ◽  
Tetsuya ANAMI ◽  
Kazuya OHGA
Keyword(s):  
Humic Substances ◽  
Electrochemical Detection ◽  
Size Exclusion Chromatography ◽  
Anodic Dissolution ◽  
High Performance ◽  
Copper Electrode ◽  
Size Exclusion ◽  
Aquatic Humic Substances ◽  
Exclusion Chromatography

Characterization of humic substances by means of high-performance size exclusion chromatography

1996 ◽  
Vol 22 (5) ◽  
pp. 489-494 ◽  
Author(s):  
Dag Hongve ◽  
Jøran Baann ◽  
Georg Becher ◽  
Synne Lømo
Keyword(s):  
Humic Substances ◽  
Size Exclusion Chromatography ◽  
High Performance ◽  
Size Exclusion ◽  
Exclusion Chromatography

scholarly journals Periplasmic synthesis and purification of the human prolactin antagonist Δ1-11-G129R-hPRL

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Miriam F. Suzuki ◽  
Larissa A. Almeida ◽  
Stephanie A. Pomin ◽  
Felipe D. Silva ◽  
Renan P. Freire ◽  
...  
Keyword(s):  
Size Exclusion Chromatography ◽  
High Performance ◽  
Signal Sequence ◽  
Osmotic Shock ◽  
Size Exclusion ◽  
Specific Expression ◽  
E Coli ◽  
Human Prolactin ◽  
Exclusion Chromatography

AbstractThe human prolactin antagonist Δ1-11-G129R-hPRL is a 21.9 kDa recombinant protein with 188 amino acids that downregulates the proliferation of a variety of cells expressing prolactin receptors. Periplasmic expression of recombinant proteins in E. coli has been considered an option for obtaining a soluble and correctly folded protein, as an alternative to cytoplasmic production. The aim of this work was, therefore, to synthesize for the first time, the Δ1-11-G129R-hPRL antagonist, testing different activation temperatures and purifying it by classical chromatographic techniques. E. coli BL21(DE3) strain was transformed with a plasmid based on the pET25b( +) vector, DsbA signal sequence and the antagonist cDNA sequence. Different doses of IPTG were added, activating under different temperatures, and extracting the periplasmic fluid via osmotic shock. The best conditions were achieved by activating at 35 °C for 5 h using 0.4 mM IPTG, which gave a specific expression of 0.157 ± 0.015 μg/mL/A600 at a final optical density of 3.43 ± 0.13 A600. Purification was carried out by nickel-affinity chromatography followed by size-exclusion chromatography, quantification being performed via high-performance size-exclusion chromatography (HPSEC). The prolactin antagonist was characterized by SDS-PAGE, Western blotting, reversed-phase high-performance liquid chromatography (RP-HPLC) and MALDI-TOF–MS. The final product presented > 95% purity and its antagonistic effects were evaluated in vitro in view of potential clinical applications, including inhibition of the proliferation of cancer cells overexpressing the prolactin receptor and specific antidiabetic properties, taking also advantage of the fact that this antagonist was obtained in a soluble and correctly folded form and without an initial methionine.

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