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Biocatalysts: The Different Classes and Applications for Synthesis of APIs
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
The aldolase-catalyzed reaction proceeds via two different mechanisms, a Schiff base formation (class I aldolases) or by Zn2+ activation (class II aldolases), as depicted in the opposite scheme for DHAP-dependent enzymes. The mechanism of class I aldolases (a) is characterized by the formation of an imine between the terminal amino group of a Lys residue and the carbonyl oxygen atom of the substrate DAHP. The imine may rearrange to an enamine that attacks nucleophilicly the aldehyde carbonyl carbon. Subsequent hydrolysis gives the new aldol and the free enzyme. The first steps in the reaction mechanism of the class II aldolases such as tagatose-1,6-diphosphate aldolase or fructose-1,6-diphosphate aldolase (b) are the binding of DAHP and the abstraction of a proton from the activated C1 by a functional group of the active site. The following steps (not shown), are glyceraldehyde-3-phosphate binding with subsequent C–C bond formation, and proton transfer.
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:
Molecular Aspects of the Activity and Inhibition of the FAD-Containing Monoamine Oxidases
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
The reaction catalysed by MAO removes two hydrogen atoms from the amine forming an imine, and reduces FAD. The reduced FAD is then reoxidized by oxygen to form hydrogen peroxide. The imine product is hydrolysed by water giving the corresponding aldehyde and ammonia (Fig. 10.2). This chapter will consider the structure of the enzyme and the redox reaction with the cofactor and before turning to the substrate specificity, kinetics and mechanism that are important for drug design. MAO A and MAO B show broad specificity for both substrates and inhibitors, yet can display exquisite selectivity as will be discussed in the last section on inhibitors.
Synthesis, characterisation, biological evaluation and in silico studies of sulphonamide Schiff bases
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2020
Mustafa Durgun, Cüneyt Türkeş, Mesut Işık, Yeliz Demir, Ali Saklı, Ali Kuru, Abdussamat Güzel, Şükrü Beydemir, Suleyman Akocak, Sameh M. Osman, Zeid AlOthman, Claudiu T. Supuran
In this study, the sulphonamides containing imine group (1–4) were synthesised and then, the secondary amine sulphonamides (5–8) were obtained through reduction of the imine derivatives (1–4) according to literature methods82. 3-Aminobenzenesulfonamide and 4-aminobenzenesulfonamide were condensed with 3-bromo-2-hydroxybenzaldehyde and 3-chloro-2-hydroxybenzaldehyde in the presence of catalytic amounts of formic acid. In separate reactions, imine compounds synthesised as above were then reduced with NaBH4 to obtain the novel secondary amine sulphonamides. The synthesis of the imine (1–4) and amine (5–8) sulphonamide compounds are illustrated in Scheme 1. The synthesised imine (1–4) and amine (5–8) derivatives were obtained as solid products, stable at room temperature.
Assessment of the antiproliferative and apoptotic roles of sulfonamide carbonic anhydrase IX inhibitors in HeLa cancer cell line
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2019
Ismail Koyuncu, Ataman Gonel, Mustafa Durgun, Abdurrahim Kocyigit, Ozgur Yuksekdag, Claudiu T. Supuran
The aromatic sulfonamides used in this study were reported in our previous study13. Briefly, the imine compound derivatives (A1-A3) were synthesised through the reaction of 4–(2-aminoethyl)benzenesulfonamide with substituted aromatic aldehydes with catalytic amounts of formic acid in methanol at the refluxing temperature for 3–5 h. The secondary amine derivatives (B1-B3) were prepared by reduction of the imine compounds (A1-A3) with NaBH4 in methanol. All the derivatives of imine and amine were characterised with both analytical and spectral data. The aromatic aldehydes used in the synthesis were 5-chloro-2-hydroxybenzaldehyde (A1,B1), 3,5-dichloro-2-hydroxybenzaldehyde (A2, B2), and 2-hydroxybenzaldehyde (A3, B3). These CA inhibitors have been shown to induce a moderately effective, reversible inhibition of the membrane-bound isozyme CA IX compared with traditional inhibitors. The KIs of the CA inhibitors and the chemical structures of the inhibitors tested are shown in Table 113.
Molecular structure investigation towards pharmacodynamic activity and QSAR analysis on hypoxanthine using experimental and computational tools
Published in Egyptian Journal of Basic and Applied Sciences, 2018
G. Susithra, S. Ramalingam, S. Periandy, R. Aarthi
The present compound was the composition of pyrimidine and imidazole rings and basically its derivatives was found to be good drug. Moreover, since, the present compound was found to be drug itself, the rate of chemical property for the cause of drug activity was investigated. Accordingly, in this work, several analyses have been made which symbolized the drug activity and the entire experimental and theoretical studies proved that, the present compound was exposed its drug property and was ensured from the literature work. Here, the compound has many imine functional groups which are the main source of drug behaviour. It was also ensured by frontier molecular energy transition, electronic CT complex analysis and NMBO profile. The biological activity parameter analysis has also proved goodness of the drug. The compound itself without substitutions was acted as antibiotic drug and if the suitable substitutions added in appropriate places, the molecular complex will may be acted as good anticancer drug.