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Effect of Elevated CO2 Conditions on Medicinal Plants
Published in Azamal Husen, Environmental Pollution and Medicinal Plants, 2022
Anuj Choudhary, Antul Kumar, Harmanjot Kaur, Mandeep Singh, Gurparsad Singh Suri, Gurleen Kaur, Sahil Mehta
In addition, there is an enhanced allocation of carbon to the leaves, stems, and roots of a plant. As a result of this, plants become taller and produce maximum biomass during higher carbon dioxide conditions. Singh et al. (2018) observed that night leaf respiration (NLR) was suppressed under elevated carbon dioxide conditions. It was reported that there is a rapid decline in leaf respiration when the partial pressure of atmospheric CO2 increased (Ghannoum et al. 2000). The mechanism behind this respiration reduction is not fully elucidated yet, but it may be due to dark carbon dioxide fixation PEPc (phosphoenolpyruvate carboxylase), change in cytosolic pH, and alteration in enzyme membranes (Tan et al. 2020).
Distribution and Biological Functions of Pyruvate Carboxylase in Nature
Published in D. B. Keech, J. C. Wallace, Pyruvate Carboxylase, 2018
Pyruvate carboxylase has been shown to be a constitutive component of yeast,156,355,710 though the level of its activity and its actual contribution to anaplerotic carbon dioxide fixation can vary depending on the growth conditions.619
Metabolism of Glutamate and Glutamine in Neurons and Astrocytes in Primary Cultures
Published in Elling Kvamme, Glutamine and Glutamate in Mammals, 1988
It has often been suggested that glucose serves as a precursor of transmitter amino acids in neurons.67,77,78 After labeling with [14C]glucose, both cellular pools of aspartate and glutamate and releasable pools of these two amino acids in cerebellar granule cells are labeled (Table 4). This labeling does, however, not mean that a net synthesis of glutamate or aspartate has taken place, since it is a prerequisite for a net conversion of glucose to, for example, glutamate that an anaplerotic process occurs, e.g., a carbon dioxide fixation catalyzed by PC (Figure 1). Since this enzyme is absent from neurons,24,46,47 no net synthesis of glutamate or aspartate can occur in isolated neurons.
Tough amphiphilic antifouling coating based on acrylamide, fluoromethacrylate and non-isocyanate urethane dimethacrylate crosslinker
Published in Biofouling, 2020
Vishal Vignesh, Thi Hoang Ha Nguyen, Lyndsi Vanderwal, Shane Stafslien, Anthony Brennan
Polyurethane-based acrylic chemistries have been used in AF applications and have been shown to have enhanced anti-microbial activity (Xu et al. 2017). The classical polymerization of polyurethanes involves the reaction of polyol and isocyanate. The isocyanate is, however, a toxic substance and has been shown to have genotoxic, mutagenic, and carcinogenic effects (Nakashima et al. 2002). A non-toxic alternative for the conventional isocyanate-based polyurethane is the non-isocyanate urethane which is typically formed by the reaction of a cyclic carbonate with an amine, has a porosity of 3-5 times lower and a chemical resistance of 30-40% higher than conventional polyurethanes (Kathalewar et al. 2013). Non-isocyanate polyurethanes have been synthesized by reacting bio-based epoxidized vegetable oil, castor oil and carbonated soybean oil with different diamines (Lovell et al. 2001; Lee and Deng 2015; Datta and Włoch 2016). Catalytic carbon dioxide fixation by carbonation of glycerol, trimethylolpropane and pentaerythritol glycidyl ether, followed by curing with citric acid amino amides in the presence of cellulose carbonate, represents an attractive green chemistry route to non-isocyanate polyurethanes (NIPU) and bio-based NIPU composites (Figovsky et al. 2005; Fleischer et al. 2013). UV-stable hybrid non-isocyanate PU coatings, named green polyurethane™ were made of UV-resistant oligomers containing cyclic carbonate, epoxy and amino groups (Figovsky et al. 2005, 2013; Fleischer et al. 2013). Dicarbamates and diols have also been used to synthesize NIPUs. The non-toxic dicarbamates have been synthesized using dimethyl carbonate in the presence of methanol and a tertiary amine base by the Lossen rearrangement (Unverferth et al. 2013).
Carbon- versus sulphur-based zinc binding groups for carbonic anhydrase inhibitors?
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2018
Simple molecules/ions such as CO2, bicarbonate and protons are essential in many important physiologic processes in all life kingdoms (Bacteria, Archaea, and Eukarya) and for this reason, relatively high amounts of carbonic anhydrases (CAs, EC 4.2.1.1), the enzymes which use these molecules/ions as substrates, are present in most of the investigated organisms, all over the phylogenetic tree1–13. There are seven genetically distinct CA families known to date4–7. The α-CAs are present in vertebrates, arthropods, sponges, corals, fungi, protozoa, algae, and cytoplasm of green plants but also in many Bacteria species1,7–13. β-CAs are predominantly found in Bacteria, algae, and chloroplasts of both mono- as well as dicotyledons, but also in many fungi and some Archaea1–9. The γ-CAs were found in Archaea, Bacteria, and plants1–13, whereas the δ-, ζ-, and θ-CAs seem to be present only in marine diatoms2. The η-CAs were found to date only in protozoa of the Plasmodium type5. In all these organisms, CAs catalyse the reversible hydration of carbon dioxide to bicarbonate and protons (hydronium ions), and are involved in crucial physiological processes connected with respiration and transport of CO2/bicarbonate, pH and CO2 homeostasis, electrolyte secretion in a variety of tissues/organs, biosynthetic reactions (e.g. gluconeogenesis, lipogenesis and ureagenesis), bone resorption, calcification, tumourigenicity, and many other physiologic or pathologic processes (thoroughly studied in vertebrates)1–13. In algae, plants and some bacteria they play an important role in photosynthesis and other biosynthetic reactions10. In diatoms, CAs play a crucial role in carbon dioxide fixation4,10. Many such enzymes from vertebrates, protozoa, fungi, and bacteria are well-known drug targets1–13, and their inhibitors possess pharmacologic applications, being clinically used for the management of glaucoma1,14, edema1,15, obesity16, epilepsy17, hypoxic tumors1,2,18,19, idiopathic intracranial hypertension20, etc. Ultimately, some human (h) CA isoforms have also been validated as drug targets for cerebral ischemia21, neuropathic pain22, and arthritis23, whereas many such enzymes present in pathogenic organisms may lead to the development of anti-infectives with a new mechanism of action24,25.
Effect of amino acids and amines on the activity of the recombinant ι-carbonic anhydrase from the Gram-negative bacterium Burkholderia territorii
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2021
Viviana De Luca, Andrea Petreni, Vincenzo Carginale, Andrea Scaloni, Claudiu T. Supuran, Clemente Capasso
Enzyme activation implies that a chemical compound binding to an enzyme favourably affects the corresponding catalysed reaction rate1. Among the activators, worth mentioning are ions, small organic molecules (amines and amino acids, but also other derivatives), as well as peptides, proteins, and lipids1,2. Enzyme activation is classified as essential and non-essential. In the first case, the enzymatic reaction occurs only when the activator is present; in the second case, the catalysed reaction takes place with or without the activator3,4. Enzymatic reactions using ATP as substrate, such as those catalysed by kinases, are an excellent example of processes undergoing enzyme activation5. The suitable substrate for these biocatalysts is the complex formed by ATP and Mg2+ (the ion acting as activator), and the reaction does not take place when Mg2+ is absent and ATP is present5. In contrast, an elegant and well-described example of non-essential activation is represented by the superfamily of carbonic anhydrases (CAs, EC 4.2.1.1), which are widely investigated by us and others as drug targets6–13. These enzymes are involved in the catalysis of a pivotal physiological reaction, the reversible hydration of carbon dioxide to bicarbonate and protons10,13–18. Members of the CA superfamily are grouped into eight classes (α, β, γ, δ, ζ, η, θ and ι) according to their structural characteristics, and are distributed in all living organisms, starting from microorganisms to multicellular plants/animals13–17. For example, mammalian genomes encode only for numerous isoforms of the α-CA class and accomplish specialised functions in various tissues and organs19–23. In plants, α- and β-CAs have an essential role in photosynthesis and biosynthetic reactions related to it9. In simpler organisms, such as bacteria, Archaea and cyanobacteria, α-, β-, γ- and ι-CAs are present, which have a role in balancing the [CO2]/[HCO3-] ratio and the carbon dioxide fixation9–11,13,18,24. Marine diatoms encode for α-, δ-, ζ-, θ- and ι-CAs, which are involved in carbon dioxide fixation and metabolism25–27. In addition to α- and β-forms, protozoan species also expressed η-CAs. These enzymes are involved in de novo purine/pyrimidine biosynthetic pathways28. Finally, organisms of the fungal kingdom generally present enzymes of the β-class, which are present at least in one isoform29–31. Fungal CO2-sensing is directly stimulated by HCO3−, which is produced in a CA-dependent manner31–34.