Components of Nutrition
Christopher Cumo in Ancestral Diets and Nutrition, 2020
Preoccupation with numbers may ignore more salient issues. The tussle over how much protein to consume might be compared to a debate over the amount of air to breathe. If it is full of soot and other pollutants, a person should inhale as little as possible and move to a pristine area. In a similar vein, nutritional quality is at least as crucial as quantity because not all proteins are identical. Their components, amino acids, determine quality. Amino acids are fundamental molecules with amine and carboxyl groups, both defined earlier. The body can manufacture from other compounds at least half the twenty amino acids that comprise all life.64 But it cannot make eight to ten, depending on whom the reader consults, which the diet must supply, and which are therefore essential.65 In addition, premature newborns and adults with liver damage may require amino acids that are normally unessential.66
Methods of Protein Iodination
Erwin Regoeczi in 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:
Protein and amino acids
Jay R Hoffman in Dietary Supplementation in Sport and Exercise, 2019
Amino acids are organic substances containing both amino and acid groups. Due to variations in their side chains, amino acids possess different biochemical properties (67). At physiological pH, amino acids are typically stable in aqueous solutions, hence their robust half-life in the human circulation (85). Skeletal muscle corresponds to 40–45% of the total body mass of humans and represents the largest reservoir of peptide-bound and free amino acids in the body (22). During catabolism, each amino acid has its own specific pathway of oxidation. Biochemically, significant metabolites of amino acids include ammonia, carbon dioxide (CO2), long- and short-chain fatty acids, glucose, hydrogen sulphide (H2S), ketone bodies, nitric oxide, urea, uric acid, polyamines and other nitrogenous compounds (11, 44). Moreover, the complete oxidation of amino acids occurs only if their carbons are ultimately converted to acetyl-CoA, a molecule which is then oxidized to CO2 and water (H2O) in the mitochondria by way of the Krebs cycle and electron transport system (85). The use of protein, on a molar basis, as a fuel source is much less efficient for ATP production compared to fat and carbohydrate. For example, the efficiency of energy transfer from amino acids to ATP ranges from only 29% for methionine to 59% for isoleucine. Although, glutamine is a preferred fuel source for non-muscle cells such as enterocytes, lymphocytes and macrophages (20, 60).
Novel amides of mycophenolic acid and some heterocyclic derivatives as immunosuppressive agents
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2022
Juliusz Maksymilian Walczak, Dorota Iwaszkiewicz-Grześ, Michalina Ziomkowska, Magdalena Śliwka-Kaszyńska, Mateusz Daśko, Piotr Trzonkowski, Grzegorz Cholewiński
For A1, A8, A11, and A14 cases, 2.0 equivalents of tertiary amine (DIPEA) were applied due to standard procedure present in the literature35. However, in most cases only 1.0 equivalent was utilised on account of reaction mechanism. Initially, each reaction was carried out in a manner consistent with the reaction mechanism, but the one proposed in the literature was also studied. Differences in the base amounts may happen due to the high stability of salt formed upon MPA and amine dissolution. Increasing the amount of DIPEA alters pH balance which affects the tendency of amine to react with activated MPA as it may less readily occur in protonated form. Base excess is believed to increase coupling rates and to disrupt hydrogen bonds responsible for conformation stabilisation which affects the availability of amino groups36. A3 was synthesised with individual quantities of base and activating agent used which were developed through the optimisation process. Due to the potential N-acyl 2-aminobenzo[d]-1H-imidazole isomerisation processes observed between annular and exocyclic nitrogen atoms, two products would occur. However, 1H NMR spectrum proved N-acylation at the exocyclic nitrogen as an additional peak close to 12 ppm was observed (one annular, one amide, and one phenolic protons all deshielded in the magnetic field). Isomerisation and tautomerisation phenomena may affect reaction outcomes, e.g. decreasing yields as for A3.
An updated patent review on monoamine oxidase (MAO) inhibitors
Published in Expert Opinion on Therapeutic Patents, 2022
Paolo Guglielmi, Simone Carradori, Ilaria D’Agostino, Cristina Campestre, Jacobus P. Petzer
The monoamine oxidase (MAO, EC.1.4.3.4) enzymes exist as two isoforms that are protein products of distinct genes [1]. These isoforms, termed MAO-A and MAO-B, are highly similar on both the amino acid sequence level and with respect to their three-dimensional structures [2,3]. In particular, the structures of their active sites are highly conserved with only 6 amino acids (among 16 active site residues) differing between the two isoforms [4,5]. Both enzymes use a covalently linked flavin adenine dinucleotide (FAD) cofactor to catalyze the oxidation of amine substrates at the α-carbon [6]. This yields the corresponding aldehyde product, while ammonia (for primary amines) and hydrogen peroxide are generated as side products [7]. Hydrogen peroxide is produced from the reduction of molecular oxygen, which occurs when the reduced flavin is reoxidized [8]. Among the various amines utilized as substrates, neurotransmitter amines are the most noteworthy. In accordance with the structural similarities between MAO-A and MAO-B, a significant overlap in substrate specificity exists with dopamine, noradrenaline, adrenaline, and tyramine acting as substrates for both isoforms. In contrast, serotonin is a specific substrate for MAO-A, while benzylamine and 2-phenethylamine are selective for MAO-B [9].
PDE1 inhibitors: a review of the recent patent literature (2008-present)
Published in Expert Opinion on Therapeutic Patents, 2022
Mei-Ling Le, Mei-Yan Jiang, Chuan Han, Yi-Yi Yang, Yinuo Wu
In 2015, Kehler and coworkers disclosed a series of PDE1 inhibitors with quinazoline scaffold (Figure 27). The X group on the quinazoline was a halogen atom in the first patent. The IC50 values of these compounds against PDE1 ranged from 7 nM to 2800 nM. Most compounds in this patent had two or more stereoisomers and one showed better inhibitory activities than others [79]. For the representative compound 86, stereoisomer 1 gave the IC50 value of 9.9 nM, while stereoisomer 2 gave the IC50 value of 65 nM against PDE1B. However, no configuration was provided for each stereoisomer. In another patent by Kehler, the X group on the quinazoline was instead by the methoxy group. The amine can be primary amine, secondary amine, or cyclic aliphatic amine [80]. The configuration had a significant impact on the inhibitory activities. For example, the (S)-87 was 30-fold more potent against PDE1B than (R)-87 [81].
Related Knowledge Centers
- Ammonia
- Biogenic Amine
- Chemical Compound
- Chemistry
- Functional Group
- Substituent
- Amino Acid
- Nitrogen
- Hydrogen
- Trimethylamine