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1
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Purification, crystallization and properties of triosephosphate isomerase from human skeletal muscle

100%
Dąbrowska A., Kamrowska I., Baranowski T.
Acta Biochimica Polonica
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1978
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vol. 25
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issue 3
247-256
2
Content available remote

CEA-negative glioblastoma and melanoma cells are sensitive to cytosine deaminase/5-fluorocytosine therapy directed by the carcinoembryonic antigen promoter.

88%
Dąbrowska A., Szary J., Kowalczuk M., Szala S., Ugorski M.
Acta Biochimica Polonica
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2004
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vol. 51
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issue 3
723-732
EN
Recent studies have suggested that carcinoembryonic antigen (CEA)-promoter sequences are active only in CEA-positive cells, filing in the criteria for tumor specific targeting of suicide genes. However, the present study on gene therapy of colon cancer and cell-specificity of CEA promoter, provide evidence that CEA-positive and CEA-negative cells transfected with E. coli cytosine deaminase (CD) gene under the control of CEA promotor sequence are sensitive to enzyme/pro-drug therapy with 5-fluorocytosine (5-FC). Individual clones derived from the CEA-negative cell lines: melanoma Hs294T and glioblastoma T98G after transfection with CD differed profoundly in their sensitivity to 5-FC. The IC50 values for several clones of the CEA-negative cells were almost the same as for CEA-positive colon cancer cells. Such 5-FC-sensitive clones derived from the population of CEA-negative cells, present even in small number, because of the very effective bystender effect of this enzyme/pro-drug system can cause severe problems during therapy by efficiently killing surrounding normal cells. Safety is the major issue in gene therapy. Our data suggest that the safety of gene-directed enzyme pro-drug therapy (GDEPT) with CEA promoter driven expression of therapeutic genes is not so obvious as it has originally been claimed.
3
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Application of Asian pumpkin (Cucurbita ficifolia) serine proteinase for production of biologically active peptides from casein

76%
Dąbrowska A., Szołtysik M., Babij K., Pokora M., Zambrowicz A., Chrzanowska J.
Acta Biochimica Polonica
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2013
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vol. 60
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issue 1
117-122
EN
The main objective of this study was to determine potential application of a serine proteinase derived from Asian pumpkin for obtaining biologically active peptides from casein. The course of casein hydrolysis by three doses of the enzyme (50, 150, 300 U/mg of protein) was monitored for 24 hours by the determinations of: hydrolysis degree DH (%), free amino group content (μmole Gly/g), RP HPLC peptide profiles and by polyacrylamide gel electrophoresis. In all hydrolyzates analyzed antioxidant activities were determined using three tests: the ability to reduce iron ions in FRAP test, the ability to scavenge free radicals in DPPH test, and Fe2+ chelating activity. The antimicrobial activity of obtained peptide fractions was determined as the ability to inhibit the growth of Escherichia coli, Bacillus cereus and Pseudomonas fluorescens in a diffusion plate test. The deepest degradation, expressed as the DH [%] and the free amino group content (67% and 7528 µmole Gly/mg, respectively), was noted in samples hydrolyzed with 300 U/ml of enzyme for 24 hours, while in other samples the determined values were about three and two times lower. The results were in agreement with the peptide profiles obtained by RP HPLC. The highest antioxidative activities determined in all tests were seen for the casein hydrolysate obtained with 300 U/mg protein of serine proteinase after 24 h of reaction (2.15 µM Trolox/mg, 96.15 µg Fe3+/mg, 814.97 µg Fe2+/mg). Antimicrobial activity was presented in three preparations. In other samples no antimicrobial activity was detected.
4
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The use of serine protease from Yarrowia lipolytica yeast in the production of biopeptides from denatured egg white proteins

64%
Pokora M., Zambrowicz A., Zabłocka A., Dąbrowska A., Szołtysik M., Babij K., Eckert E., Trziszka T., Chrzanowska J.
Acta Biochimica Polonica
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2017
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vol. 64
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issue 2
245-253
EN
Deriving non-conventional enzymes from cheaper sources than those used for commercially available enzymes may result in the production of hydrolysates with beneficial features, while drastically reducing the cost of hydrolysis. This is especially significant for enzymatic hydrolysis as a method of protein waste utilization. We have previously described the ability of non-commercial serine protease from Yarrowia lipolytica yeast to produce/release bioactive peptides from egg white protein by-products (EP). The enzymatic hydrolysis of EP was carried out for 24 h using the serine protease at an enzyme: substrate ratio of 1:30 (w/w). The obtained hydrolysate was characterized by protein degradation of 38% and also exhibited an antioxidant and cytokine-inducing activity. The isolation procedure (ultrafiltration and RP-HPLC) of bioactive peptides from the EP hydrolysate provided peptide fractions with significant antioxidant and ACE inhibitory activities. Three homogeneous and three heterogeneous peptide fractions were identified using MALDI-TOF/MS and the Mascot Search Results database. The peptides, mainly derived from ovalbumin, were composed of 2-19 amino-acid residues. We have thus demonstrated a novel ability of serine protease from Y. lipolytica to release biopeptides from an EP by-product.
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