XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
240
T2: P–25
Synthesis and conformational studies of small peptides
based on middle sized ring lactams
Maria Owińska
1
, Barbara Rys
2
, and Edward Szneler
2
1
A Faculty of Materials Science and Ceramics, AGH University of Science and Technology,
Mickiewicza 30, 30-059 Kraków, Poland, owinska@agh.edu.pl
2
Department of Organic Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland
The secondary structure of the proteins can be divided into α-helix, β-sheet and reverse
turns. A reverse turn is defined as a site where a polypeptide chain reverses its overall direction.
It leads the chain to fold back on itself by almost 180°. There are several types of reverse turns.
The three-residue γ-turn and four-residue β-turn are among the most commonly studied reverse
motifs [1]. Turns have been suggested to play very important role in protein folding, molecular
recognition and receptor binding [2–4].
In the present work, the synthesis and conformational analysis of amide derivatives of 7- and
8-membered lactams and natural amino acids (Ala, Phe, Leu, Met, Pro), was carried out (Fig. 1).
The aim of conformational studies was to determine whether this compounds can adopt
geometries characteristic for γ or β reverse turns.
Fig.1. Structures of investigated compounds.
The conformational preferences of the molecules of the investigated compounds, in the
solution, were determined using nuclear magnetic resonance, and the DFT methods. The
temperature dependence of the amide protons chemical shifts [Δδ(NH)/ΔT], the Δδ(NH) upon
addition of solvent able to compete for the formation of hydrogen bonds and NOESY/ROESY
experiments, have been used to assess which amide protons are involved in intramolecular
hydrogen bonds.
Based on molecular modeling and theoretical calculations it was found that majority of
compounds prefer to adopt conformation characteristic for γ-turns. The presence of classical and
inverse γ-turns as well as two consecutive γ-turns in the molecular structure, was indicated.
They can be stabilized by intramolecular hydrogen bonding. The influence of the dipeptides
structure like lactam ring type and amino acid side chain on molecular structures have been
studied.
Keywords: reverse turn; hydrogen bond; conformation
References
[1] K. C. Chou, Anal. Biochem. 286 (2000) 1.
[2] E. Vass, M. Hollόsi, F. Besson, R. Buchet, Chem. Rev. 103 (2003) 1917.
[3] A. M. C. Marcelino, L.M. Gierasch, Biopolymers 89 (2008) 380.
[4] A. Singh, M. L. Dirain, A. Wilczynski, C. Chen, B. A. Gosnell, A. S. Levine, A. S. Edison, C.
Haskell-Luevano, ACS Chem. Neurosci. 5 (2014) 1020.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
241
T2: P–26
Comparison of the fatty acids content, iodine value and smoke point of
the blends for deep-frying with their primary oleic components
Lucyna Dymińska
1
, Abduladhim Moamer M. Albegar
2
, Adam Zając
1
,
Tadeusz Czuj
3
, Wojciech Sąsiadek
1
, Jadwiga Lorenc
1
, and Jerzy Hanuza
4
1
Department of Bioorganic Chemistry, Institute of Chemistry and Food Technology, Faculty of
Engineering and Economics, Wrocław University of Economics, Komandorska 118/120, 53-345
Wrocław, Poland, e-mail: lucyna.dyminska@ue.wroc.pl
2
Faculty of Agriculture at Azzaytuna University, Azzaytuna, Libya
3
Faculty of Natural Sciences, Wrocław University, Poland
4
Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2,
50-950 Wrocław, Poland
In oil blending oils from different varieties, regions and countries are used to create a
consistent taste or fragrance for special applications. Blended essential oils are used for massage
and aromatotherapy. By blending a few oils, it is possible to achieve a scent promoting a
specific reaction such as easing tension, enhancing mood, stimulation of various substances in
brain, etc. It is well known that some oils are suitable for high-temperature frying, above 230°C,
because of their high smoke point. These applications depend on the country and region in
which avocado, palm, peanut, rice bran, safflower, sesame and sunflower oils are used for
frying. The important problem of these procedures is to answer the question if it is possible to
predict the physical, chemical and thermal parameters of the final mixture when the
characteristics of the primary components are known. In the present work the theoretical and
experimental parameters of some blends for deep-frying are compared for palm, coconut, rice
bran and rapeseed (canola) oils. The fatty acids profiles from chromatographic measurements,
iodine values from chemical and spectroscopic studies as well as smoke points from thermal
treatment have been determined for the blends and their primary components.
4000 3000
1500
1000
500
1780
1760
1740
1720
1700
A
b
s
o
rb
a
n
c
e
Wavenumber / cm
-1
A
B
C
A
b
s
o
rb
a
n
c
e
Wavenumber / cm
-1
A
B
C
Fig. 1. FTIR spectra of the studied oils: coconut (A), palm (B) and their blend 1:1 (C).
In this work it has been shown that blends of oils for special purposes can be proposed when
some physicochemical parameters of individual oils constituting the mixture are known. The
partial values of the iodine values and fatty acid profiles are additive approximating the final
parameters of the blend in a sufficient way. However, the smoke points of the final blend could
not be predicted from the additive values of the components of the mixture. Infrared spectra of
the oils and blends were recorded in the range 4000–400 cm
–1
. The FTIR spectra of palm and
coconut oils and their 1:1 blend are shown in Fig. 1.
Keywords: oils; blends; FTIR spectra
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