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1

NMR measurements of proton exchange between solvent and peptides and proteins

100%

Wójcik J., Ruszczyńska K., Zhukov I., Ejchart A.

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2

Conformational analysis of a novel cyclic enkephalinanalogue using NMR and EDMC calculations

100%

Sidor M., Wójcik J., Pawlak D., Izdebski J.

Acta Biochimica Polonica

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1999

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vol. 46

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issue 3

641-650

3

Cyclic enkephalin-deltorphin hybrids containing a carbonyl bridge: structure and opioid activity

73%

Ciszewska M., Ruszczyńska K., Oleszczuk M., Chung N., Witkowska E., Schiller P., Wójcik J., Izdebski J.

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2011

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vol. 58

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issue 2

225-230

EN

Six hybrid N-ureidoethylamides of octapeptides in which an N-terminal cyclic structure related to enkephalin was elongated by a C-terminal fragment of deltorphin were synthesized on MBHA resin. The synthetic procedure involved deprotection of Boc groups with HCl/dioxane and cleavage of the peptide resin with 45 % TFA in DCM. d-Lys and d-Orn were incorporated in position 2, and Lys, Orn, Dab, or Dap in position 5. The side chains of the dibasic amino function were protected with the Fmoc group. This protection was removed by treatment with 55 % piperidine in DMF, and cyclization was achieved by treatment with bis-(4-nitrophenyl)carbonate. Using various combinations of dibasic amino acids, peptides containing a 17-, 18-, 19- or 20-membered ring structure were obtained. The peptides were tested in the guinea-pig ileum (GPI) and mouse vas deferens (MVD) assays. Diverse opioid activities were observed, depending on the size of the ring. Extension of the enkephalin sequence at the C-terminus by a deltorphin fragment resulted in a change of receptor selectivity in favor of the δ receptor. The conformational propensities of selected peptides were determined using the EDMC method in conjunction with data derived from NMR experiments carried out in water. This approach allowed proper examination of the dynamical behavior of these small peptides. The results were compared with those obtained earlier with corresponding N-(ureidoethyl)pentapeptide amides.

4

Light conditions alter accumulation of long chain polyprenols in leaves of trees and shrubs throughout the vegetation season.

73%

Bajda A., Chojnacki T., Hertel J., Swiezewska E., Wójcik J., Kaczkowska A., Marczewski A., Bojarczuk T., Karolewski P., Oleksyn J.

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2005

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vol. 52

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issue 1

233-241

EN

In many plants belonging to angiosperms and gymnosperms the accumulation in leaves of long chain polyprenols and polyprenyl esters during growth in natural habitats depends on the light intensity. The amount of polyprenols in leaves is also positively correlated with the thickness of the leaf blade (SLA, specific leaf area). The polyprenol content of leaves shows seasonal changes with a maximum in autumn and a minimum in early summer with the difference between poorly and well illuminated plants persisting throughout the vegetation season.

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4 Acta Biochimica Polonica

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4 Wójcik J.

2 Izdebski J.

2 Ruszczyńska K.

1 Bajda A.

1 Bojarczuk T.

1 Chojnacki T.

1 Chung N.

1 Ciszewska M.

1 Ejchart A.

1 Hertel J.

1 Kaczkowska A.

1 Karolewski P.

1 Marczewski A.

1 Oleksyn J.

1 Oleszczuk M.

1 Pawlak D.

1 Schiller P.

1 Sidor M.

1 Swiezewska E.

1 Witkowska E.

1 Zhukov I.

NMR measurements of proton exchange between solvent and peptides and proteins

Conformational analysis of a novel cyclic enkephalinanalogue using NMR and EDMC calculations

Cyclic enkephalin-deltorphin hybrids containing a carbonyl bridge: structure and opioid activity

Light conditions alter accumulation of long chain polyprenols in leaves of trees and shrubs throughout the vegetation season.