Wyniki wyszukiwania - AGRO

1

Evolutionary principles for generating protein mimetics: Directed assembly of peptide loops on topological templates

100%

Banfi D., Mandal B., Mutter M., Patiny L.

Acta Biochimica Polonica

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2001

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tom 48

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nr 4

A novel methodology for the reversible competitive condensation of peptide loops to chemoreactive topological templates is presented.

2

Negative chronotropic effect of endothelin-1 [ET-1] in the cardiac pacemaker tissue

100%

Goraca A.

Journal of Physiology and Pharmacology

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2003

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tom 54

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nr 1

The aim of this study was to asses the direct effect of ET-1 on spontaneous discharge rate of the pacemaker tissue in the presence of isoproterenol. The experiments were performed on pacemaker tissue of the isolated right auricle of the right heart atrium of a two-day-old rat. The spontaneous discharge rate of the pacemaker tissue was recorded on the ECG apparatus and analyzed by the computer. ET-1 alone did not significantly affect the discharge rate of the pacemaker tissue. Isoproterenol rapidly increased the discharge rate of the pacemaker tissue. ET-1 had negative chronotropic effect in the presence of isoproterenol. JKC – 301, a blocker of ETA receptors, significantly reduced the negative chronotropic effect of ET-1 in the presence of isoproterenol, whereas IRL – 1038, a blocker of ETB receptors, did not significantly affect the negative chronotropic effect of ET-1 in the presence of isoproterenol. In conlusion, the negative chronotropic effect of ET-1 in the presence of beta-adrenergic stimulation the pacemaker tissue of the right auricle of the right heart atrium of the two-day-old rat is mediated by ETA receptors.

3

Peptides in lipid bilayers: structural and thermodynamic basis for partitioning and folding

100%

White S. H.

Biophysics of Membrane Transport

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1994

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tom 12

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nr 2

4

Endoglin (cd105) and S100A13 as markers of active angiogenesis in endometriosis

88%

Hayrabedyan S., Kyurkchiev S., Kehayov I.

Reproductive Biology

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2005

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tom 05

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nr 1

5

Determination of theoretical retention times for peptides analyzed by reversed-phase high-performance liquid chromatography

88%

Dziuba J., Minkiewicz P., Mogut D.

Acta Scientiarum Polonorum. Technologia Alimentaria

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2011

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tom 10

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nr 2

Background. Peptides are important components of foods mainly due to their biological activity. The basic method of their identification is reversed phase high-performance liquid chromatography coupled with electrospray-ionization mass spectrometry (RP-HPLC- -ESI-MS). Retention time (tR) prediction in silico is very helpful in analysis of multicomponent peptide mixtures. One of problems associated with RP-HPLC-ESI-MS is deterioration of mass spectra quality by trifluoroacetic acid (TFA). This problem can be avoided through the use of chromatographic columns designed for work with low TFA concentrations in mobile phase. The objective of this study was to determine the correlations between peptide retention times predicted with the use of a program available on-line and experimental retention times obtained using the column working with low TFA concentrations. Material and methods. The set of synthetic peptides and bovine α-lactalbumin fragments (18 peptides) was used in the experiment. Theoretical retention times were calculated using Sequence Specific Retention Calculator (SSRC) program. The experimental retention times were measured via RP-HPLC-ESI-MS method using column working with low TFA content. The dependence between theoretical and experimental tR was expressed via empirical equations. Results. The best correlation between theoretical and experimental retention times of peptides containing at least four amino acid residues has been obtained when third order polynomial (R2 = 0.9536). Prediction quality for diand tripeptides was significantly lower. The method described can be applied for cysteine-containing peptides although our sample preparation procedure did not include modification of this amino acid, taken into attention by SSRC program. Conclusions. The results of this study validate the usefulness of a third degree polynomial as a simple function describing the correlation between peptide retention times predicted by an on-line application and experimental retention times. The above function can effectively predict retention times in situations when experimental conditions differ from the computational environment (various columns, mobile phase composition, use or resignation from chemical modifications during sample preparation, various HPLC equipments). On-line available tR predicting application with correction based on user’s own data may be a useful tool in food peptidomics.

6

Structural biology of the influenza virus fusion peptide

88%

Worch R.

Acta Biochimica Polonica

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2014

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tom 61

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nr 3

7

CD investigations on conformation of H-X-[Pro]n-Y-OH peptides [X-Trp, Tyr; Y-Tyr, Met]; models for intramolecular long range electron transfer

88%

Wierzchowski K. L., Majcher K., Poznanski J.

Acta Biochimica Polonica

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1995

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tom 42

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nr 2

Conformations of three series of peptides: H-Trp-(Pro)n-Tyr-OH (n = 1-5), H-Trp-(Pro)n-Met-OH (n = 1-3) and H-Tyr-(Pro)n-Met-OH (n = 1-3), used as models in studies on long range electron transfer through protein matrix, were investigated by CD spectroscopy in aqueous solution at pH 5.2 in the temperature range of 10°C-90°C. CD spectra of their component N- and C-terminal dipeptide and oligoproline fragments were also measured under similar conditions. In interpretation of the spectra the cis <-> trans equilibrium about X-Pro bonds was taken into account and CD spectra of Trp-Pro and Tyr-Pro chromophores in trans and cis configuration of the peptide bond were evaluated. The spectra of n = 3-5 peptides from the first series and those with n = 2-3 from the other two series exhibit a strong negative band in the 202-207 nm region, the strength of which is proportional to the number of Pro residues in the (Pro)n bridge, and characterized by a large temperature decrement. In view of close similarity between characteristics of this band and the 206 nm band of aqueous oligoproline peptides = 3), known to attain a left handed helical conformation similar to that of 31 helix of the all-trans poly-L-proline II, this band was attributed to a conformation of the latter type. H-Trp-(Pro)2-Tyr-OH does not form this conformation due to sterical interaction between the two bulky aromatic side chains. Conclusions drawn from analysis of the CD spectra are supported by 1H and C13 NMR data reported elsewhere (Poznański et al., 1993, Biopolymers 33,781-795).

8

Immunosuppressive activity of tyrosine analogues of cyclolinopeptide A

88%

Wieczorek Z., Pedyczak A., Bodalski T., Lisowski M., Trojnar J., Zimecki M., Siemion I. Z.

Archivum Immunologiae et Therapiae Experimentalis

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1992

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tom 40

|

nr 3-4

9

Signalling protein inhibitors via the combinatorial modification of peptide scaffolds

88%

Lawrence D. S.

Cellular and Molecular Biology Letters

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2005

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tom 10

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nr Suppl.2

10

88%

Siemion I. Z., Kubik A., Zimecki M., Wieczorek Z.

Archivum Immunologiae et Therapiae Experimentalis

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1994

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tom 42

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nr 3

16

Application of high-performance liquid chromatography on-line with ultraviolet-visible spectroscopy in food science

88%

Minkiewicz P., Dziuba J., Darewicz M., Nalecz D.

Polish Journal of Food and Nutrition Sciences

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2006

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tom 15/56

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nr Spec.Issue 1

The aim of the present review was to describe the application of diode-array detectors for the identification of HPLC-separated chemical compounds on the basis of their UV/Vis spectra. Diode-array detectors serve to identify compounds containing conjugated double bonds, especially aromatic compounds, and to evaluate their purity. This group of compounds includes: peptides and proteins (in that case aromatic amino acid residues are chromophores), anthocyanins and other flavonoids, other phenolic compounds, carotenoids and other dyes. The most simple strategy of interpreting UV/Vis spectra is to determine the location of absorbance maximum in zero order spectra (such a strategy is usually applied in dye analysis). The absorbance ratio at different wavelengths was used to identify and investigate structural changes in proteins and peptides. Chemometrical analysis of zero order spectra provides a basis for evaluating peak purity and choosing the background spectrum. Derivatives of spectra may be characterised via determination of convexity intervals, location of minima of second derivative, calculation of amplitudes of second and third derivatives or similarity indices between derivatives of individual spectra. The possibilities offered by UV/Vis spectroscopy cover, among others, discrimination between spectra of proteins with different contents of aromatic amino acids (mainly tyrosine and tryptophan), as well as discrimination between spectra of anthocyanins containing the same chromophore but different glycosidic moieties.