Raw veganism
Carlo Alvaro in Raw Veganism, 2020
Cooking denatures protein. Denaturation is a modification of the molecular structure of protein by heat or by an acid that destroys or diminishes its original properties and biological activity. Denaturation means that the molecular structure of proteins is modified and, as a result, the modified structure can be harmful for the body. Thus, “Most genetic diseases can be linked back to a protein that does not have the structure it should.”38 When food is cooked, resistant linkages are formed between the amino acid chains that the body cannot separate.39 Also, the Maillard reaction negatively affects the food (typically starches) generating prooxidants, carcinogens, and lowering the nutritional value of food.40 Furthermore, cooked fats can be rendered rancid and carcinogenic.41
Towards the Importance of Fenugreek Proteins
Dilip Ghosh, Prasad Thakurdesai in Fenugreek, 2022
Various inter-molecular interactions in proteins result in their low molecular mobility, as well as high softening or melting temperature. In other words, once the protein is folded to its final native form, it is stabilized through hydrophobic and electrostatic interactions, hydrogen bonds, along with further strong covalent crosslinks. Softening of proteins requires their denaturation, meaning partial unfolding of structured native protein into an unstructured state with no or little fixed residual structures. Consequently, melting temperature of proteins could be considered as their denaturation temperature (Td). However, a complete unfolding into a fully amorphous structure may not occur as true melting means (Ricci et al., 2018). Considering that any changes in secondary, tertiary, or quaternary structures of proteins may refer to proteins denaturation, DSC not only gives insights into the differences between thermal characteristics of various proteins like legumes, but also could help to study the effects of various parameters on those attributes. Generally, denaturation of proteins is an endothermic process, owing to the heat they absorb to thermally unfold over a temperature range.
Special Problems with Biological Fluids
Joseph Chamberlain in The Analysis of Drugs in Biological Fluids, 2018
Protein can also be denatured using proteolytic enzymes, a procedure that should avoid the possibility of damage to the analyte using chemical-type denaturation. Such procedures are generally found in the preparation of tissue for drug analysis, but the enzyme subtilisin has been successfully used for the digestion of plasma proteins. Osselton82 showed that the better recoveries of drug from tissue using enzyme hydrolysis compared with direct extraction was also obtained in the analysis of whole blood and plasma. In Osselton’s procedure, 200 µl plasma is buffered to pH 10.5 with 50 µl Tris buffer, enzyme is added, and the mixture incubated at 55°C for 1 h before extraction with 50 µl butyl acetate. The organic phase is then analyzed by an appropriate method. Osselton points out that the enzyme hydrolysis is most useful for general screening procedures where it is not usually possible to optimize the normal extraction procedures for a specific compound. A number of other proteolytic enzymes have been proposed (Table 2.5), which presumably could be adapted for biological fluid assays with detriment to the cited analyte. The various methods of separating protein from solutions containing analytes are reviewed in Table 2.6.
Resonant interaction between electromagnetic fields and proteins: A possible starting point for the treatment of cancer
Published in Electromagnetic Biology and Medicine, 2018
Emanuele Calabrò, Salvatore Magazù
We know that proteins are formed by amino acids through covalent bonds between the carboxyl group of an amino acid and the amine group of another amino acid. These chains of amino acids form polypeptides that orient themselves forming hydrogen bonds between the carboxyl group and the amine group that give rise to a regular spiral named the α-helix. Nevertheless, an external stress can be able to induce the loss of a number of hydrogen bonds that gives rise to an unfolded state represented by another conformation, that is the β-sheet structure, constituted by β-strands linked by hydrogen bonds. In this state of denaturation, the proteins cannot perform at all their functions in livings. For instance, intracellular proteins should fold in the conformational state of the α-helix, and this folding process is allowed by some auxiliary proteins (Ellis & Hartl, 1992; Gething & Sambrook, 1992). Furthermore, the increase in intensity of the Amide I under exposure to MWs was already explained in Calabrò and Magazù (2017a), assuming that the α-helix structure aligns with the direction of the applied field.
Green synthesis of ZnO-NPs using endophytic fungal extract of Xylaria arbuscula from Blumea axillaris and its biological applications
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2023
Lavanya Nehru, Gayathri Devi Kandasamy, Vanaraj Sekar, Mohammed Ali Alshehri, Chellasamy Panneerselvam, Abdulrahman Alasmari, Preethi Kathirvel
Protein denaturation is the primary cause of inflammation, and the potential of the nanoparticle’s protein denaturation was investigated as a part of an inquiry into the mechanism of anti-inflammatory action [55]. Protein denaturation is a detrimental process in which a functional protein loses its biological function as a result of structural modifications spurred on by external stimuli such as chemicals, heat, etc. [56]. Anti-inflammatory activity is one of the intriguing studies that attempt to examine the protective ability of NPs rather than their destructive aspect [55]. Therefore, it is necessary to investigate the anti-inflammatory potential of the biosynthesized nanoparticles at the onset of their application as a therapeutic agent. The maximum inhibition of protein denaturation obtained employing the ZnONPs was found to be 96.77 ± 0.23% at 500 µg/mL concentration which was extremely close to the obtained value from the standard drug diclofenac sodium 98.45 ± 0.66% at maximum concentration, as shown in Table 5. Similarly, biogenic ZnONPs synthesised using L. edodes were found to inhibit protein denaturation in a dose-dependent manner with a maximum inhibition % of about 86.45 ± 0.60 in a similar trend of inhibition exhibited by diclofenac [57].
Bioanalytical strategies in drug discovery and development
Published in Drug Metabolism Reviews, 2021
Aarzoo Thakur, Zhiyuan Tan, Tsubasa Kameyama, Eman El-Khateeb, Shakti Nagpal, Stephanie Malone, Rohitash Jamwal, Chukwunonso K. Nwabufo
During denaturation, secondary and tertiary structures of the protein are removed. This allows for better protonation as more sites are revealed. The denaturing process is done by adding either an alkali or an acid to the sample or by using high-temperature and surfactants. This step can be done in a couple of different ways. In-solution denaturing can be done with urea or thiourea, followed by disulfide reduction and adding alkali to the sample. Reduction and alkylation necessarily follow this process to prevent re-folding. In gel-denaturation is an alternative to in-solution denaturing. It involves protein separation through gel electrophoresis. At times, additional sample extraction procedures, such as SPE or MWCO filtration may also be needed before injecting onto an LC-MS/MS (DelGuidice et al. 2020).
Related Knowledge Centers
- Acid
- Biochemistry
- Inorganic Compound
- Nucleic Acid
- Organic Compound
- Protein
- Protein Quaternary Structure
- Protein Secondary Structure
- Protein Tertiary Structure
- Native State