China 
Africa 
Explore chapters and articles related to this topic
Biomolecules
Published in Volodymyr Ivanov, Environmental Microbiology for Engineers, 2020
Denaturation is a change in the secondary, tertiary, or quaternary structures of proteins following the inactivation of the proteins. The environmental engineering aspects of denaturation are as follows: Thermal denaturation of proteins in pasteurization and sterilization processesDenaturation of proteins by chemical oxidants in the disinfection processDenaturation of proteins due to destruction of hydrogen bonds by organic solvent and saltsDenaturation of proteins caused by reaction of amino acids with heavy metals
Protein Adhesives
Published in A. Pizzi, K. L. Mittal, Handbook of Adhesive Technology, 2017
Charles R. Frihart, Linda F. Lorenz
Most proteins, including those used in adhesives, are globular proteins that have enough hydrophobic portions or weakly hydrophilic portions to cause the protein to fold inward in an aqueous environment (Figure 5.3). During this hydrophobic collapse, intramolecular association of hydrophobic amino acids moves them mainly to the inside of the globular structure and the polar amino acids preferentially to the outside. However, the primary and secondary structures limit the ability of particular amino acids to move to these separate regions. The polar groups on the inside of the globule are stabilized by associating with other polar groups on the chain. These types of interactions include not only hydrogen bonds, but also acid–base salt bridges and disulfides from the thiol groups. Some of the hydrophobic amino acids end up on the outside of the structure. This folding of the protein is referred to as its tertiary structure.
The Biosphere
Published in Stanley E. Manahan, Environmental Chemistry, 2022
Tertiary structures are formed by the twisting of alpha-helices into specific shapes. They are produced and held in place by the interactions of amino side chains on the amino acid residues constituting the protein macromolecules. Tertiary protein structure is very important in the processes by which enzymes identify specific proteins and other molecules upon which they act. It is also involved with the action of antibodies in blood, which recognize foreign proteins by their shape and react to them. This is basically what happens in the case of immunity to a disease where antibodies in blood recognize specific proteins from viruses or bacteria and reject them.
Green synthesis of silver nanoparticles using Caesalpinia bonducella leaf extract: characterization and evaluation of in vitro anti-inflammatory and anti-cancer activities
Published in Inorganic and Nano-Metal Chemistry, 2022
In the present study, the anti-inflammatory activity of silver nanoparticles was assessed by protein denaturation method. Protein denaturation is a process in which a protein loses its biological function due to the destruction of its secondary and tertiary structures. This may be brought about by various factors such as heat, electrolytes, pH fluctuation, or alcohol, which produce alterations in the solubility of proteins such as albumins and globulins.[51] Inflammation and protein denaturation are closely related. Protein denaturation leads to inflammation because it permits the generation of autoantigens, which are responsible for inflammation in rheumatic diseases.[52] In the present work, different concentrations of aqueous leaf extract and silver nanoparticles were subjected to evaluation of anti-inflammatory activity which was compared against the standard reference drug diclofenac sodium. A significant difference was observed between the inhibition of thermally induced protein denaturation by the leaf extract and that by the AgNPs when compared against the standard drug (100 µg/mL). The inhibitory effect of silver nanoparticles 85.67 ± 1.63% was comparable to that of diclofenac sodium 91.78 ± 1.46% while the extract showed 20.3 ± 1.45% lesser inhibitory potential compared to both the standard drug and the nanoparticles (Table 1). Our results are in agreement with the reports presented by previous workers where synthesized silver nanoparticles using Calophyllum tomentosum leaf extract and found the anti-inflammatory activity of the nanoparticles to be around 84.64 ± 1.4%.[53]
A comprehensive review on stability of therapeutic proteins treated by freeze-drying: induced stresses and stabilization mechanisms involved in processing
Published in Drying Technology, 2022
Zhe Wang, Linlin Li, Guangyue Ren, Xu Duan, Jingfang Guo, Wenchao Liu, Yuan Ang, Lewen Zhu, Xing Ren
The function of therapeutic proteins depends on their spatial structure, including primary structure, secondary structure, and tertiary structure. Changes in protein structure can lead to the loss of therapeutic protein activity. Therefore, the structural changes during the freeze-drying of therapeutic proteins are also a hot research topic. Studies had shown that freeze-drying can cause the loss of protein secondary structure. In the study of Xu et al,[78] it was found that freeze-drying caused the loss of the main secondary structure of RhGH. The results showed that there was a significant correlation between the retention of secondary structure and the degradation process of the protein during storage at 40 °C. The higher the retention of the secondary structure, the lower the rate constant of oxidation and aggregation. It was found that trehalose and sucrose can effectively retain the natural structure of protein and improve its storage stability. Despite this, it still cannot visually show the effect of freeze-drying on the conformation of therapeutic proteins. Taschner et al [87] investigated a case where the anti-idiotypic antibody MMA 383 substantially lost its immunogenicity in vivo when the protein was not degraded. The images of its Fab and Fc moieties were obtained by scanning transmission electron microscopy. The results showed that the non-lyophilized antibody had a wider shape than the recombinant lyophilized antibody, and the angle of the Fab moiety changed more, indicating greater flexibility, which indicated that lyophilization reduces the overall flexibility of the antibody. These changes may be related to the decreased immunogenicity of recombinant freeze-dried antibodies in vivo.
Exploration of ligand-induced protein conformational alteration, aggregate formation, and its inhibition: A biophysical insight
Published in Preparative Biochemistry and Biotechnology, 2018
Saima Nusrat, Rizwan Hasan Khan
Protein folding refers to the phenomenon where an unstructured polypeptide chain transforms to form an extremely organized, structured, and functional conformational state (secondary, super-secondary, tertiary, and quaternary structures) with the help of noncovalent and covalent interactions.[58,59] Proposed models for protein folding and unfolding are as follows[60]: