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Pharmaceutical Applications of Chondroitin
Published in Amit Kumar Nayak, Md Saquib Hasnain, Dilipkumar Pal, Natural Polymers for Pharmaceutical Applications, 2019
Dilipkumar Pal, Amit Kumar Nayak, Supriyo Saha, Md Saquib Hasnain
Although the basic unit of chondroitin sulfate is double sugar moiety; which formed as growing glycosaminoglycan chain with alternate addition of N-acetyl galactosamine and D-glucuronic acid (Miyata and Kitagawa, 2017). Chondroitin synthases, N-acetyl galactosamine transferase, D-glucuronic acid transferases, CS N-acetyl galactosaminyl transferase I & II, chondroitin sulfate glucuronyltransferase and CS polymerization factor catalyze the addition of N-acetyl galactosamine and D-glucuronic acid with proper coordination during chain elongation by phosphorylation or sulfation reaction, but not a single enzyme can develop the total chondroitin sulfate chain. Phosphorylation reaction on the Xyl residue present in the tetrasaccharide portion not yet recognized the required detailed analysis of the role of sulfation reaction within the CS chains (Figure 5.1). Enzymes of the carbohydrate sulfotransferase family are responsible for the sulfation modification with Chondroitin 4-sulfotransferase, chondroitin 6-sulfotransferase, and GalNAc-4 sulfate 6-O-sulfotransferase (Kwok et al., 2012). A schematic diagram showing the structure of CS. CS-glycosaminoglycans are attached to the serine residue on the core protein via a tetrasaccharide linkage.Source:Kwok et al., (2012); Copyright © 2012 with permission from Elsevier B.V.
Enzymes used to produce glycosaminoglycan mimetics from marine polysaccharides
Published in Antonio Trincone, Enzymatic Technologies for Marine Polysaccharides, 2019
Christine Delbarre-Ladrat, Véronique Verrez-Bagnis, Sylvia Colliec-Jouault, Agata Zykwinska
As discussed in the introduction of this chapter, the biological properties of sulfated GAGs are strongly influenced by the degree of sulfation and by the sulfate group distribution along the polymer (Schnabelrauch et al. 2013). The transfer reaction of sulfate group from the ubiquitous donor 3'-phosphoadenosine 5'-phosphosulfate (PAPS) to a sugar acceptor is catalyzed by carbohydrate sulfotransferases (ST) with strict specificities (Klaassen and Boles 1997; Habuchi 2000) (Figure 21.2). Two conserved domains of the protein are involved in PAPS binding: the 5'-phosphosulfate-binding site or 5'-PSB and the 3'-phophate-binding site or 3'-PB (Kakuta et al. 1998; Rath et al. 2004). Except for these motifs, STs show limited sequence similarity (Rath et al. 2004).
Metabolism and Toxicity of Occupational Neurotoxicants: Genetic, Physiological, and Environmental Determinants
Published in Lucio G. Costa, Luigi Manzo, Occupatinal Neurotoxicology, 2020
Stefano M. Candura, Luigi Manzo, Anna F. Castoldi, Lucio G. Costa
The addition of an inorganic sulfate moiety to a hydroxyl group is a major route of conjugation for both endogenous and foreign compounds. The reaction is catalyzed by cytosolic sulfotransferases, a group of enzymes found primarily in liver, kidney, intestinal tract and lungs, and requires the coenzyme 3’-phosphoadenosine-5’-phosphosulfate (PAPS).3 There are four classes of sulfotransferases: aryl sul-fotransferase, which conjugates phenols, catecholamines, and organic hydroxyl-amines; hydroxy steroid sulfotransferase, which conjugates hydroxy steroids and certain primary and secondary alcohols; estrone sulfotransferase, which is active on phenolic groups in the aromatic ring of steroids; and bile salt sulfotransferase.1
Xenobiotic metabolism and transport in Caenorhabditis elegans
Published in Journal of Toxicology and Environmental Health, Part B, 2021
Jessica H. Hartman, Samuel J. Widmayer, Christina M. Bergemann, Dillon E. King, Katherine S. Morton, Riccardo F. Romersi, Laura E. Jameson, Maxwell C. K. Leung, Erik C. Andersen, Stefan Taubert, Joel N. Meyer
Sulfotransferase enzymes (SULTs) catalyze the conjugation of a sulfonate group from a donor molecule, typically 3-phosphoadenosine-5ʹ-phosphosulfate or PAPS, to a substrate (at a hydroxyl or amino functional group). SULTs might either be membrane-bound in the Golgi apparatus, where they metabolize endogenous molecules, or soluble in the cytosol, where they metabolize xenobiotic and endogenous substrates. The human genome encodes up to 14 SULTs, while the C. elegans genome encodes a single cytosolic sulfotransferase enzyme, ssu-1 (also termed Y113G7A.11 and ceST1)(Hattori et al. 2006). There is no apparent knockdown phenotype, although it is a suppressor of unc-1 and unc-24 phenotypes (thus the naming ssu, or suppressor of stomatin mutant uncoordination)(Carroll et al. 2006). Its enzymatic properties were investigated biochemically by recombinant protein expression, and the C. elegans SULT enzyme sulfonated prototypical hydroxylated substrates including 4-nitrophenol and 2-naphthol as well as bisphenol A but did not metabolize monoamines or hydroxysteroids. Hattori et al. (2006). created antibodies against the recombinant protein and were able to detect expression in cytosolic fractions of C. elegans lysate and induction by the substrate isophenylpropanol. The mRNA is also highly induced in dauer larvae, indicating a potential role for sulfonation in dauer signaling (Hattori et al. 2006).
Benzo[a]pyrene osteotoxicity and the regulatory roles of genetic and epigenetic factors: A review
Published in Critical Reviews in Environmental Science and Technology, 2022
Jiezhang Mo, Doris Wai-Ting Au, Jiahua Guo, Christoph Winkler, Richard Yuen-Chong Kong, Frauke Seemann
During phase II xenobiotic metabolism reactions, BaP metabolites are conjugated with hydrophilic moieties (glutathione, glucuronic acid, or sulfate) by enzymes, including glutathione S-transferases (GSTs), uridine diphosphate–glucuronosyl transferases (UGTs), and sulfotransferases (SULTs) to increase their water solubility for easy excretion through urines and feces (Figure 1) (Moffat et al., 2015; Willett et al., 2000; Xue & Warshawsky, 2005).