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Fundamentals of Modern Peptide Synthesis
Published in Mesut Karahan, Synthetic Peptide Vaccine Models, 2021
Amino acids in peptides and proteins are linked together with a peptide bond. The peptide bond is a chemical bond formed between two molecules of amino acids when the carboxyl group of one molecule reacts with the amino group of the other molecule, releasing a molecule of water. This is a dehydration synthesis reaction (also known as a condensation reaction), and usually occurs between amino acids. Dipeptide is the structure formed by the combination of two amino acids with amide bond. Likewise, as amino acids are added, we may have tripeptides, tetrapeptides, and other polypeptides. Gradually, when the structure moves towards quaternary structures, it is called protein (Raven et al. 2014; Reece et al. 2011).
Toxicology Studies of Semiconductor Nanomaterials: Environmental Applications
Published in Suresh C. Pillai, Yvonne Lang, Toxicity of Nanomaterials, 2019
T. P. Nisha, Meera Sathyan, M. K. Kavitha, Honey John
The synthesis can be done inside the living organisms so that bio-detoxification and bio-mineralization takes place along with the advantage of having enzymes which catalyse the synthesis reaction. So far, many nanosemiconductors have been prepared in different living organisms. Cadmium sulphide was the first nanosemiconductor to be prepared in a biological system by Dameron et al. (1989). The yeast cells were cultured with cadmium salts where the cadmium ions were chelated with amino acid and reacted with intracellular sulphide to produce CdS crystallites. Similarly, PbS and ZnS (Mala et al., 2014) were also prepared. E. coli have been used as a biofactory to synthesise different semiconductor nanomaterials including CdZn, CdSe, CdTe, and SeZn with controlled size by varying the metal ion concentration. The semiconductor QDs showed enhanced fluorescence, which was further used for imaging human fibroblast cells (Park et al., 2010, Sweeney et al., 2004).
Nutrition for health and sports performance
Published in Nick Draper, Helen Marshall, Exercise Physiology, 2014
As suggested by its name, a synthesis (or combination) reaction involves bond formation between atoms and/or molecules to form larger, more complex molecules. The formation of water from hydrogen and oxygen molecules is an example of a synthesis reaction. A simple synthesis reaction can be represented as:
Different chemical proteomic approaches to identify the targets of lapatinib
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
Tatjana Kovačević, Krunoslav Nujić, Mario Cindrić, Snježana Dragojević, Adrijana Vinter, Amela Hozić, Milan Mesić
The synthesis of the lapatinib analogues was achieved starting from 1 and yielded molecules 2–4. All transformations were focused on the secondary amine functionality of 1. These modifications (amidation) changed secondary amino group from basic to neutral in the case of compounds 2 and 3, while for molecule 4 an alkylation reaction preserved the basicity of this centre. The synthesis of molecules 2–4 was accomplished using the approach described in Scheme 1, in each one or two synthesis reaction steps. To access compound 2, amidation of lapatinib 1 was performed with 2-(tert-butoxycarbonylamino)acetic acid using polymer-supported carbodiimide (PS-CDI), hydroxybenzotriazole (HOBT) and N,N-diisopropylethylamine (DIPEA) in DCM/DMF at room temperature. After isolation and purification of the protected intermediate, tert-butoxycarbonyl protecting group (BOC) was removed using trifluoroacetic acid (TFA) in DCM at room temperature. The final molecule 2 was purified by flash chromatography on prepacked silica columns. Similarly, we used the same chemistry to amidate compound 1 with propargylacetic acid, to yield compound 3. To prepare lapatinib with a dual tag functionality (4), we initially needed to prepare the bromobenzyl intermediate 5.
Antitumor activity of the third generation EphA2 CAR-T cells against glioblastoma is associated with interferon gamma induced PD-L1
Published in OncoImmunology, 2021
Zhijing an, Yi Hu, Yue Bai, Can Zhang, Chang Xu, Xun Kang, Shoubo Yang, Wenbin Li, Xiaosong Zhong
Samples containing 2 µg total RNA each were used as input material for generating the sequencing libraries using the NEBNext®Ultra™ RNA Library Prep Kit (#E7530L, NEB) following the manufacturer’s. Briefly, mRNA was purified from total RNA using poly-T oligo-attached magnetic beads. Fragmentation was carried out using divalent cations under elevated temperature in NEB Next First Strand Synthesis Reaction Buffer (5X). First-strand cDNA was synthesized using random hexamer primers and RNase H. Second strand cDNA synthesis was subsequently performed using buffer, dNTPs, DNA polymerase I, and RNase H. The library fragments were purified with QiaQuick PCR kits, eluted with EB buffer, and then terminal repair, A-tailing, and adapters were implemented. To complete the library, the products were retrieved and PCR was performed. The clustering of index-coded samples was performed on a cBot Cluster Generation system with TruSeq SR Cluster kit, v3-cBot-HS (Illumina Inc.), according to the manufacturer’s protocol. Subsequently, the library was subjected to an Illumina NovaSeq 6000 System platform (Illumina Inc.) for sequencing. Raw data were first processed using custom Perl scripts. Clean data (clean reads) were read by removing reads containing poly-N with 5′- adapter contaminants, without 3′- adapter or the insert tag, or containing poly-A, -T, -G or -C from raw data, as well as low-quality reads.
Preparation of psoralen polymer–lipid hybrid nanoparticles and their reversal of multidrug resistance in MCF-7/ADR cells
Published in Drug Delivery, 2018
Qingqing Huang, Tiange Cai, Qianwen Li, Yinghong Huang, Qian Liu, Bingyue Wang, Xi Xia, Qi Wang, John C. C. Whitney, Susan P. C. Cole, Yu Cai
FTIR analysis was used to characterize any chemical (formation of chemical bonds) changes that occurred in the polymer due to the addition of drug during the synthesis reaction. Figure 2(f) shows the FTIR spectra of PSO, blank-PLN, PSO + PLN, and PSO-PLN. The presence of PSO in PLN can be analyzed through its characteristic carbonyl absorption peak. It can be seen from Figure 2(f) that carbonyl can be observed in the PSO monomer and physical mixture. But there is no obvious carbonyl absorption peaks in the infrared scanning pattern of PSO-PLN, blank-PLN, which indicated that PSO may form a new crystal in PLN.