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Principles of Chemistry
Published in Arthur T. Johnson, Biology for Engineers, 2019
Enzymes are the regulators of biological metabolism. Chemical reaction rates in the absence of enzymes are too slow to maintain life. Enzymes allow intracellular processes to adjust to new environmental factors and to reach the point where growth can occur. This system can be regulated in two ways: (1) the stimulation or inhibition of enzyme activity and (2) the induction or repression of enzyme synthesis (Figure 3.9.1). The product of enzyme activity, or compounds derived from those products, can act as inhibitors of enzyme activity. There are two possible mechanisms for this (Figure 3.9.2): (1) the presence of large amounts of product can inhibit the conversion of substrate through the law of mass action and a reversible biochemical reaction, or (2) the product may be a potent competitive inhibitor for the substrate (called feedback inhibition).
Biological Waste Treatment
Published in Syed R. Qasim, Wastewater Treatment Plants, 2017
Microorganisms grow and obtain their energy from substrates utilizing very complex and intricate biochemical reactions. Several enzymes are involved in a series of reactions forming a sequence of enzyme-substrate complexes, which are then converted to a product and the original enzyme. The enzymes are proteins that act as catalysts. Enzymes are also specific to each substrate and have a high degree of efficiency in converting the substrate to the end products. The enzymes are extracellular and intracellular. Extracellular enzymes convert the substrate to a form that can diffuse into the cell. The intracellular enzymes bring about oxidation, synthesis, and energy reactions within the cell. The enzyme activity, however, is substantially affected by pH, temperature, and substrate concentration.
Machine Learning in Metabolic Engineering
Published in Shampa Sen, Leonid Datta, Sayak Mitra, Machine Learning and IoT, 2018
Enzyme activity is generally manipulated by certain effectors (inhibitors or activators) that bind to the enzyme, thus influencing its job as a catalyst. The response coefficient describes the influence exerted by such an effector (ei) on the flux of the metabolite (Jk): RXiJk=eiJkdJkdei Another coefficient—the elasticity coefficient—expresses the relationship between metabolite concentration (Xj) and rate of the reaction (νi), both of which are system variables: εXji=Xjνi∂νi∂Xj Going back to the analogy of a metabolic pathway with a factory layout, we get to know what changes need to be made at which points in the factory layout and by how much, after performing metabolic control analysis. Hereafter, the biochemical engineer performs genetic engineering or other techniques to effectively change the factory processes.
Determination of bacterial intracellular and extracellular biotransformation compounds and biodegradation of kerosene based industrial rolling oils via gas chromatography-mass spectrometry
Published in Bioremediation Journal, 2019
Nyashadzashe P. Masvingwe, Sumaiya F. Jamal-Ally
Methyl laurate treatment (Tables 8 & 9) shows the hydrocarbon compounds detected after 1 week of treatment with A. aegrifaciens. In comparison to the uninoculated control, the following compounds were common to both samples: Heptane, 2,4-dimethyl; Ethylbenzene; p-Xylene and Dodecanoic acid, methyl ester indicating resistance to biotransformation. The new compounds formed (Tables 8 & 9) included isoalkanes and n-alkanes. Subterminal oxidation and methylation were the probable modes of activation for the biodegradation of the oil. Methyl-substituted isoalkanes were the dominant group of new compounds which suggests that methylation was more active than subterminal oxidation. This is probably because of the abundance of the methyl groups in the oil. Enzymes involved in methylation therefore had an increased substrate concentration. One of the factors that affects enzyme activity is substrate concentration where a greater concentration translates to greater enzyme activity (Fogarty and Kelly 2012).
Current approaches for the exploration of antimicrobial activities of nanoparticles
Published in Science and Technology of Advanced Materials, 2021
Nur Ameera Rosli, Yeit Haan Teow, Ebrahim Mahmoudi
On the other hand, enzymes are a class of proteins that catalyze diverse biochemical reactions by elevating the rate of reaction in the cells and are crucial in controlling biological homeostasis in living organisms [23]. Blocking enzyme activity is known as enzyme inhibition and is either reversible or irreversible. Enzymes are known to be vital virulence factors during bacterial infections. For instance, bacterial urease produced by E. coli, K. pneumonia, P. aeruginosa, Enterobacter spp., Proteus mirabilis (P. mirabilis) and Providencia stuartii (P. stuartii), are a virulence factor during urinary tract infections [75]. Hence, the inhibition of these enzymes is an important strategy to tackle infections, as has been well-documented in the literature. In one study, Ag NPs or Au NPs capped with ciprofloxacin, an antibiotic, demonstrated substantial improvement in their inhibition of bacterial urease [76]. In another, ZnO NPs of a small particle size showed strong antimicrobial activity against MRSA and could potentially inhibit the activity of β-galactosidase (GAL) [77]. Raffi et al. found that the treatment of E. coli with Ag NPs inhibited respiratory enzymes, resulting in overproduction of ROS and disrupting bacterial DNA replication, and thus suggesting that NPs had affected DNA polymerase [78]. Au NPs have been determined to interfere with enzyme functions, given their reactivity: their interference with thiol groups present in vital enzymes led to excessive production of ROS and caused cell death [79]. Additionally, Au NPs and Ag NPs have been found to tend to target phosphorus- and sulfur-containing soft bases present in DNA molecules [23]. These interactions between NPs and targeted soft bases both hinder bacteria growth and interfere with the integrity of bacterial cells. Recent studies have collectively suggested that NPs are capable of directly or indirectly inhibiting enzymatic activity and exerting antimicrobial effects.