Determination of conformational changes of polyphenol oxidase and peroxidase in peach juice during mild heat treatment using FTIR spectroscopy coupled with chemometrics

2021 ◽  
Author(s):  
Hande Baltacıoğlu ◽  
Katibe Sinem Coruk
Keyword(s):  
Heat Treatment ◽  
Ftir Spectroscopy ◽  
Polyphenol Oxidase ◽  
Conformational Changes ◽  
Mild Heat ◽  
Peach Juice

scholarly journals Investigation of protein–protein interactions by isotope‒edited Fourier transformed infrared spectroscopy

2004 ◽  
Vol 18 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Tiansheng Li
Keyword(s):  
Ftir Spectroscopy ◽  
Conformational Changes ◽  
Protein Interactions ◽  
Isotope Labeling ◽  
Structural Information ◽  
Protein Complexes ◽  
Secondary Structures ◽  
Receptor Complex ◽  
Protein Protein Interactions

Recent advance in FTIR spectroscopy has shown the usefulness of13C uniform isotope labeling in proteins to study protein–protein interactions.13C uniform isotope labeling can significantly resolve the spectral overlap in the amide I/I′ region in the spectra of protein–protein complexes, and therefore allows more accurate determination of secondary structures of individual protein component in the complex than does the conventional FTIR spectroscopy. Only a limited number of biophysical techniques can be used effectively to obtain structural information of large protein–protein complex in solution. Though X‒ray crystallography and NMR have been used to provide structural information of proteins at atomic resolution, they are limited either by the ability of protein to crystallize or the large molecular weight of protein. Vibrational spectroscopy, including FTIR and Raman spectroscopies, has been extensively employed to investigate secondary structures and conformational dynamics of protein–protein complexes. However, significant spectral overlap in the amide I/Iʹ region in the spectra of protein–protein complexes often hinders the utilization of vibrational spectroscopy in the study of protein–protein complex. In this review, we shall discuss our recent work involving the application of isotope labeled FTIR to the investigation of protein–protein complexes such as cytokine–receptor complexes. One of the examples involves G‒CSF/receptor complex. To determine unambiguously the conformations of G‒CSF and the receptor in the complex, we have prepared uniformly13C/15N isotope labeled G‒CSF to resolve its amide Iʹ band from that of its receptor in the IR spectrum of the complex. Conformational changes and structural stability of individual protein subunit in G‒CSF/receptor complex have then been investigated by using FTIR spectroscopy (Li et al.,Biochemistry29 (1997), 8849–8859). Another example involves BDNF/trkB complex in which13C/15N uniformly labeled BDNF is complexed with its receptor trkB (Li et al.,Biopolymers67(1) (2002), 10–19). Interactions of13C/15N uniformly labeled brain‒derived neurotrophic factor (BDNF) with the extracellular domain of its receptor, trkB, have been investigated by employing FTIR spectroscopy. Conformational changes and structural stability and dynamics of BDNF/trkB complex have been determined unambiguously by FTIR spectroscopy, since amide I/Iʹ bands of13C/15N labeled BDNF are resolved from those of the receptor. Together, those studies have shown that isotope edited FTIR spectroscopy can be successfully applied to the determination of protein secondary structures of protein complexes containing either the same or different types of secondary structures. It was observed that13C/15N uniform labeling also affects significantly the frequency of amide IIʹ band, which may permit the determination of hydrogen–deuterium exchange in individual subunit of protein–protein complexes.

A novel approach for the discrimination of culture medium from Vascular Endothelial Growth Factor (VEGF) overexpressing colorectal cancer cells

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Sinem Tunçer ◽  
Rafig Gurbanov
Keyword(s):  
Colorectal Cancer ◽  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Ftir Spectroscopy ◽  
Cancer Cells ◽  
Lower Amount ◽  
Vascular Endothelial ◽  
Colorectal Cancer Cells ◽  
Endothelial Growth Factor

AbstractObjectivesThe expression level of Vascular Endothelial Growth Factor (VEGF) is assumed as a prognostic marker for several tumor types, including colorectal cancer. Therefore, the determination of pre- and post-therapy levels of VEGF appears to have great value in the assessment of tumor prognosis. Enzyme-Linked Immunosorbent Assay (ELISA) is commonly used for the determination of serum or plasma VEGF levels, but the method is costly and time-consuming. In this study, we aimed to describe a rapid and cost-effective analysis method to discriminate VEGF overexpressing colorectal cancer-derived conditioned medium (CM).MethodsAttenuated Total Reflection (ATR)-Fourier Transform Infrared (FTIR) spectroscopy, combined with Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA), was used to differentiate VEGF overexpressing colorectal cancer cell line CM from CM obtained from the corresponding control cells which express and secrete relatively lower amount of VEGF.ResultsSamples belong to VEGF overexpressing colorectal cancer cells were clearly distinguished from the control group with very high PC scores as PC1 + PC2 = 96%. Besides, a 100% accurate distinction between these two groups was achieved by the LDA analysis.ConclusionsATR-FTIR spectroscopy combined with pattern recognition techniques was able to discriminate CM of VEGF overexpressing colorectal cancer cells with high efficiency and accuracy.

scholarly journals A thermo-mechanical machining method for improving the accuracy and stability of the geometric shape of long low-rigidity shafts

2021 ◽  
Author(s):  
Antoni Świć ◽  
Arkadiusz Gola ◽  
Łukasz Sobaszek ◽  
Natalia Šmidová
Keyword(s):  
Heat Treatment ◽  
Cross Section ◽  
Mechanical Treatment ◽  
Geometric Shape ◽  
Different Dimensions ◽  
Thermo Mechanical Treatment ◽  
Mechanical Machining ◽  
Simultaneous Heat ◽  
Accuracy And Stability

AbstractThe article presents a new thermo-mechanical machining method for the manufacture of long low-rigidity shafts which combines straightening and heat treatment operations. A fixture for thermo-mechanical treatment of long low-rigidity shafts was designed and used in tests which involved axial straightening of shafts combined with a quenching operation (performed to increase the corrosion resistance of the steel used as stock material). The study showed that an analysis of the initial deflections of semi-finished shafts of different dimensions and determination of the maximum corrective deflection in the device could be used as a basis for performing axial straightening of shaft workpieces with simultaneous heat treatment and correction of the initial deflection of the workpiece. The deflection is corrected by stretching the fibers of the stock material, at any cross-section of the shaft, up to the yield point and generating residual stresses symmetrical to the axis of the workpiece. These processes allow to increase the accuracy and stability of the geometric shape of the shaft.

Study of the Possible Migration of the Components of Polyethylene Terephthalate and Polyamide Films into Oils at Heat Treatment of Food Products

2020 ◽  
Vol 839 ◽  
pp. 124-130
Author(s):  
Vladimir Ananiev ◽  
Olga Bannikova ◽  
Yulia Filinskaya ◽  
Mishel Chernov
Keyword(s):  
Heat Treatment ◽  
Ftir Spectroscopy ◽  
Absorption Spectra ◽  
Polyethylene Terephthalate ◽  
Rapeseed Oil ◽  
Food Products ◽  
Spectroscopy Method ◽  
Oil Absorption ◽  
Thermal Influence

The FTIR spectroscopy method was used to investigate the changes in palm, sunflower and rapeseed oil at thermal influence up to 195°C, and also in contact with polyethylene terephthalate (PET) and polyamide (PA-6) film for 1 hour 50 minutes. It has been found that heating the oil to 195°C in contact with PET and PA-6 film does not lead to any noticeable changes in the IK oil absorption spectra. Peaks characteristic of polymers (in areas of 1535 and 1634 cm-1), are not observed.

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