Biomedical subjects

Vladas-Algirdas Bumelis

Publications and source records attributed to Vladas-Algirdas Bumelis.

4 recordsLinked to original sources

PubMed2006

Production of recombinant mink growth hormone in E. coli.

Escherichia coli cells expressing mink (Mustela vison) growth hormone were grown in a batch fermentation process. The expression level was estimated to be 27% of the total cellular protein after 3 h of induction with 1 mM isopropyl beta-D-thiogalactoside (IPTG). If the expression of mink growth hormone (mGH) was induced with 0.2 mM IPTG, the concentration of target protein was slightly lower and was found to be 23% at the same time after induction. mGH expressed as inclusion bodies was solubilized in 8 M urea and renatured by dilution protocol at a protein concentration of 1.4-2.1 mg/ml in the presence of glutathione pair in a final concentration of 11.3 mM. [GSH]/[GSSG] ratio equal to 2/1 was used. Two-step purification process comprising of ion-exchange chromatography on Q-Sepharose and hydrophobic chromatography on Phenyl-Sepharose was developed. Some 25-30 mg of highly purified and biologically active mGH was obtained from 4 g of biomass. The method presented in this study allows producing large quantities of mGH and considering initiation of scientific investigation on mGH effect on mink in vivo and availability in fur industry.

Animals↗

PubMed2006

Examination of dye-protein interaction by gel-permeation chromatography.

The interaction of Cibacron blue F3G-A with two therapeutic proteins, recombinant human growth hormone and recombinant human interferon-alpha2b, has been examined by applying gel-permeation chromatography in combination with the absorption difference spectroscopy. The complexes of these proteins with Cibacron blue F3G-A have been isolated, and their absorbance spectra have been registered. The influence of Cibacron blue F3G-A on the oligomeric state of proteins has been investigated. It was found that Cibacron blue F3G-A promotes the generation of interferon-alpha2b dimers at pH 5.0.

Chromatography, Gel↗

PubMed2006

Protein scission by metal ion-ascorbate system.

About 14 proteins were tested for specific oxidative scission catalyzed by metal ions in the presence of ascorbate and oxidizing agents (O(2) or hydrogen peroxide). Only four of them were degraded by Fe(3+)/Fe(2+)- ascorbate, twelve - by Cu(2+)/Cu(+)-ascorbate and two proteins (alpha- and beta-caseins) were degraded by Pd(2+) ions. The rate and the intensity of degradation are very different for various proteins. For the most of tested proteins only a small fraction of molecules was degraded. None of them was degraded completely. Two possible reasons of protein stability against oxidative degradation may be proposed as follows: either there is no metal binding site in a protein molecule, or metal binding ligands of protein undergo a rapid oxidative modification and the metal ion is released from the binding site. Human growth hormone was cut specifically at two sites by Cu(2+)/Cu(+)-ascorbate system. At least one of amino acid residues of this protein was modified by formation of reactive carbonyl.

Ascorbic Acid↗

PubMed2006

Congo red interaction with alpha-proteins.

The ability of Congo red to form complexes with alpha-proteins, human growth hormone and human interferon-alpha2b, was found by absorption difference spectroscopy. A human growth hormone-Congo red complex was isolated by gel-permeation chromatography, and its visible absorption spectrum was registered in comparison to free dye. The ability of Congo red to induce dimerization of human growth hormone was demonstrated using chemical cross-linking agents 1,3,5-triacryloyl-hexahydro-s-triazine and ethylene glycol bis(succinimidylsuccinate).

Biophysics↗