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Methods of Protein Iodination
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
An acyl group is the univalent group, , where R is any organic group attached to one bond of the bivalent carbonyl group ,. The alkyl group has already been defined in Section C.1.a. An aryl group is an organic group derived from an aromatic hydrocarbon by the removal of a hydrogen (e.g., the phenyl group, C6H5-, derived from benzene, C6H6). Amines are organic derivatives of ammonia (NH3) formed by the replacement of one, two, or three of the hydrogen atoms by an alkyl or aryl group; correspondingly, the resulting aliphatic and aromatic (and other) amines are classified as primary (RNH2), secondary (R2NH), or tertiary (R3N) amines. Amides are carboxylic acid derivatives obtained by the replacement of the OH group of an acid by an amino group (NH2). Azo compounds are organic compounds which contain the group, -N:N-, attached to two alkyl or aryl groups (e.g., azobenzene, C6H5-N:N-C6H5). In contrast, only one of the two N atoms bonded together in diazo compounds is attached to a carbon of an organic structure (RN=N, see further below). Imines, containing the grouping, -CH=N-, arise from the condensation of primary amines with aldehydes (or ketones) through the loss of H2O. Imides are nitrogen analogs of anhydrides:
Organotin Chemistry
Published in Nate F. Cardarelli, Tin as a Vital Nutrient:, 2019
These compounds were believed to be arsenic analogs of azobenzene and were written as dimers with As=As double bonds. However, it is now known that they are cyclic oligomers or polymers.97,98
Spectroscopy and Fluorimetry
Published in Joseph Chamberlain, The Analysis of Drugs in Biological Fluids, 2018
Jahnchen and Levy230 have described an assay for phenylbutazone which avoids the usual interference by barbiturates in the simpler procedure by Burns et al.347 In this procedure, permanganate oxidation is used to form azobenzene, absorbing at 314 nm (Figure 4.6).
Novel approaches to targeted protein degradation technologies in drug discovery
Published in Expert Opinion on Drug Discovery, 2023
Yu Xue, Andrew A. Bolinger, Jia Zhou
In 2019, Carreira’s group reported the first photoswitchable PROTAC [57]. By inducing an ortho-F4-azobenzene linker, they constructed a light-sensitive PROATC, photoPROTAC-1 (38), to realize the light-control degradation of BRD2. The azobenzene moiety acted as a switch to transform 38 into an active azo-trans-isomer upon irradiation at 415 nm, after which the linker length was adjusted to form a stable ternary complex, leading to subsequent BRD2 degradation. Notably, this transformation was reversible. When irradiated at 530 nm, an inactive trans-to-cis transformation occurred, thereby eliminating POI degradation. Furthermore, persistent degradation could be achieved without continuous irradiation due to the bistable nature of the azobenzene switch. Jiang’s group reported Azo-PROTAC-4C (39), which was derived from dasatinib (a BCR-ABL inhibitor) by installing azobenzene onto CRBN ligand [58]. Under 361 nm ultraviolet A (UVA), it induced the degradation of ABL and BCR-ABL in K562 cells, while UVC (200 ~ 280 nm) irradiation caused partial trans-to-cis conversion. Trauner’s group designed a series of photoswitchable PROTACs by engaging azobenzene or diazocine groups onto different attachment sites of published PROTACs (dBET1 and dFKBP-1) [59]. Under irradiation at 390 nm, PHOTAC-I-3 (40) induced degradation of BRD2/3/4 in RS4;11 cells, while PHOTAC-II-5 (41) induced FKBP12 degradation.
Hypoxia responsive nano-drug delivery system based on angelica polysaccharide for liver cancer therapy
Published in Drug Delivery, 2022
Xue Liu, Zhenfeng Wu, Chunjing Guo, Huimin Guo, Yanguo Su, Qiang Chen, Changgang Sun, Qingming Liu, Daquan Chen, Hongjie Mu
Hypoxia, as an important microenvironment of solid tumors, creates a physical barrier. It is an imperative reason for angiogenesis, tumor metastasis, and enhancement of the drug resistance (Teicher, 1994; Harrison & Blackwell, 2004). This barrier will be a challenge for most anticancer drugs to reach the tumor site, which limits the therapeutic effect of drugs (Primeau et al., 2005). Following consideration of the limitation of the microenvironment of hypoxia on tumor treatment, two ways are proposed, which are ‘overcoming the hypoxia’ and ‘dodging the hypoxia’ (Hu et al., 2020). The former means increasing the oxygen content of tumor tissue; the latter refers to the use of water/gas molecules in tumor tissue to enhance the therapeutic effect of hypoxia tumors and weaken oxygen dependence. Apart from that two ways, the strategy of ‘using the hypoxia’ is accepted. A new nanocarrier including azobenzene (AZO) and nitroimidazole (Liu et al., 2015; Lee et al., 2017; Liu et al., 2017; Yang et al., 2019; Shen et al., 2021) can be constructed by using the oxygen-deficient response sensitive bond, so as to realize the stimuli-responsive release of the drug under the tumor microenvironment. So that it can greatly enhance the drug concentration at the tumor site and enhance the chemotherapy effect. In fact, azobenzene is a well-known example of the hypoxia-sensitive factor. The main chain of the carrier material can be easily broken relying on the reduction reaction in a low oxygen environment, and then triggers the release of the drug.
Light mediated drug delivery systems: a review
Published in Journal of Drug Targeting, 2022
UV light has been used to influence the contents of amphipathic nano-sized block co-polymers (BCPs) for the sustainable discharge of drugs [23,32,33]. The photoisomerization capability from trans-cis of azobenzene as a part of a BCP is favourable for changes in morphology and subsequently functional properties. A poly (methacrylate) -poly (ethylene oxide)- azobenzene BCP changed its structural moieties when exposed to 365 nm UV illumination [34]. Matyjaszewski's group demonstrated that upon UV irradiation, the polymeric micelle of a BCP was synthesised using a photochromic hydrophobic spiropyran and hydrophilic poly (ethylene oxide) [35]. The micelles formed from an aqueous solution of the BCP were disrupted when illuminated with UV light and subsequently regenerated when visible light was applied to it. The disruption caused by UV light can be a hydrophobic/hydrophilic shift, primary chain degradation, reversible cross-linking, and breakage of block junction [36]. Also, UV light is used in micelles having photocleavable linkers that can be added to the side chain, middle block junction, or form the core of the polymer being used as a carrier. Depending on whether the moieties are hydrophobic, hydrophilic, and, photochromic the substrate can either destabilise partially or disintegrate completely [37,38].