China 
Africa 
Explore chapters and articles related to this topic
Arsenals of Pharmacotherapeutically Active Proteins and Peptides: Old Wine in a New Bottle
Published in Debarshi Kar Mahapatra, Swati Gokul Talele, Tatiana G. Volova, A. K. Haghi, Biologically Active Natural Products, 2020
6-N-methyllysine is obtained by transmethylation of lysine. Methylation of lysine is important in transcriptional regulation and double-strand break repair of DNA molecule in many organisms [7]. Post translation carboxylation of glutamic acid residues in proteins, results in γ-carboxyglutamate [8]. 4-hydroxyproline and 5-hydroxylysine, unusual amino acids, are an important part of collagen [6]. As these are not essential amino acids, they are synthesized by the organisms and not obtained from the diet. Desmosine is formed by four lysine molecules linked together forming a pyridinium ring. Desmosine helps in the cross-linking of elastin [9]. Ornithine is an important part of the urea cycle and the precursor of citrulline and arginine [10]. Norvaline is a component of antifungal peptides in bacteria. This unusual amino acid is also found to be present in recombinant proteins synthesized using bacterial cells [11].
Triticum Aestivum L.): Effects on the Distribution of Protein Sub-Fractions, Amino Acids, and Starch Characteristics
Published in Megh R. Goyal, Susmitha S. Nambuthiri, Richard Koech, Technological Interventions in Management of Irrigated Agriculture, 2018
Divya Jain, Bavita Asthir, Deepak Kumar Verma
GOT is a pyridoxal phosphate-dependent enzyme present in cytoplasmic and mitochondrial forms. GOT is the main enzyme involved in NH4+ assimilation.104 This enzyme is also known as aspartate aminotransferase and is one of the most active enzymes in the cell. It exists in mitochondrial and cytosolic variants. The metabolic importance of this enzyme is that it brings about a free exchange of amino groups between glutamate (which is the most common amino acid) and aspartate which is a second major amino acid pool. Glutamate and aspartate are each required for separate but essential steps in the urea cycle. The free movement of nitrogen between the glutamate and aspartate pools is an important balancing process that is vital for normal cellular metabolism. The urea cycle consists of five reactions: two mitochondrial and three cytosolic (Table 10.1). The cycle converts two amino groups, one from NH4+ and one from ASP, and a carbon atom from HCO3−, into the relatively non-toxic excretion product urea at the cost of four “highenergy” phosphate bonds (three ATP hydrolyzed to two ADP and one AMP). Ornithine is the carrier of these carbon and nitrogen atoms.
Enzymatic Amino Acid Deprivation Therapies Targeting Cancer
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Carla S. S. Teixeira, Henrique S. Fernandes, Sérgio F. Sousa, Nuno M. F. S. A. Cerqueira
Arginase I (ArgI) is the only of the two isozyme types with demonstrated anti-cancer therapeutic potential. It is a cytosolic enzyme found predominantly in liver hepatocytes, where it catalyses the hydrolysis of l-ARG to l-ornithine and urea. This is the final cytosolic step of the urea cycle, which detoxifies ammonia in mammals (Krebs, 1973). l-ornithine can be further metabolized to polyamines via ornithine decarboxylase (ODC). Then, it can generate l-proline via ornithine aminotransferase (OAT), or it can be converted to citrulline by ornithine transcarbamylase (OTC) (Morris Jr., 2002).
Hepatic proteomic assessment of oral ingestion of titanium dioxide nano fiber (TDNF) in Sprague Dawley rats
Published in Journal of Environmental Science and Health, Part A, 2022
Worlanyo E. Gato, Ji Wu, Isaac Appiah, Olivia Smith, Haresh Rochani
To explore the effects of TDNF ingestion in Sprague Dawley rats, a proteomics approach was used. Proteomics is a useful tool to evaluating the complete structure and function of proteins in an organism.[22] More than 400 hundred proteins were identified to be involved in TDNF effects in the liver. Some of these include Acyl-coenzyme A synthetase ACSM2, mitochondrial (Accession#: O70490), Betaine–homocysteine S-methyltransferase 1 (Accession#: O09171), Acyl-CoA dehydrogenase family member 11 (Accession#: B3DMA2) and Ornithine transcarbamylase, mitochondrial precursor (Accession#: P00481) among many more. These proteins are involved in such processes as catalysis of fatty acids by CoA, homocysteine metabolism, beta oxidation and the condensation of carbamoyl phosphate in the urea cycle.[23–25]
Assessment of surface water quality of the bois river (Goiás, Brazil) using an integrated physicochemical, microbiological and ecotoxicological approach
Published in Journal of Environmental Science and Health, Part A, 2022
Samara Silva Soares, Gessyca Gonçalves Costa, Lara Barroso Brito, Gisele Augusto Rodrigues de Oliveira, Paulo Sérgio Scalize
Un-ionized ammonia has been reported toxic to freshwater organisms at concentrations ranging from 0.11 to 22.6 mg/L,[40] but these toxic levels are both pH and temperature-dependent.[45] Most teleost fish are ammoniotelic, excreting up to 90% of their nitrogenous waste directly into the environment as ammonia.[46] Early-life stages of fish do not present a functional gill, which is the primary site of nitrogen excretion in juvenile and adult fishes.[47] Moreover, researchers suggest that the embryo and larval detoxification system is through a functional ornithine urea cycle to produce urea[46,48,49] and ammonia excretion is limited by a lack of ammonia transporters.[46]
Non-targeted metabolomics analyses by mass spectrometry to explore metabolic stress after six training weeks in high level swimmers.
Published in Journal of Sports Sciences, 2021
Robin Pla, Estelle Pujos-Guillot, Stéphanie Durand, Marion Brandolini-Bunlon, Delphine Centeno, David B. Pyne, Jean-François Toussaint, Philippe Hellard
One of the results that opens up prospects for future research is the significantly higher ionic concentration (~200%) of 4-phenylbutanic acid-O-sulphate in the two swimmers who reported the lowest levels of fatigue, the highest levels of motivation and the best sleep in the study. The moxocarboxylic 4-phenylbutyric acid is produced endogenously at the cell membrane level. This molecule has been identified as a chemical chaperone known to assist proteins in their maturation by improving, in particular, the folding capacity of the endoplasmic reticulum. They serve as a “quality control system”, recognising, retaining and targeting misfolded proteins for degradation (Welch & Brown, 1996). Investigators have suggested the potential role of these chemical chaperones in the treatment of stress-related neurodegenerative diseases but also in diabetes (Lee et al., 2011). Sodium phenylbutyrate is the salt of 4-phenylbutyric acid and used in the treatment of diseases such as urea cycle disorders by ammonia uptake (Ozcan et al., 2006). Sodium phenylbutyrate can reduce oxidative stress has anti-inflammatory effects, and improves insulin sensitivity and promotes glucose metabolism in skeletal muscle (Ozcan et al., 2006; Lee et al., 2011). We speculate the higher concentrations of 4-phenylbutanic acid-O-sulphate in the two swimmers who reported less subjective fatigue, higher motivation and better sleep quality suggests a relationship between peripheral membrane chemical metabolism and behavioural indices. Understanding the mechanisms of this possible interaction requires future research.