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Omics Approaches for the Production of the Microbial Enzymes and Applications
Published in Pankaj Bhatt, Industrial Applications of Microbial Enzymes, 2023
Heena Parveen, Anuj Chaudhary, Parul Chaudhary, Rabiya Sultana, Govind Kumar, Priyanka Khati, Meenakshi Rana, Pankaj Bhatt
Dehydrogenases are oxidoreductases that can be found in bacteria, yeast, plants, and animals [30–34]. Dehydrogenases use a coenzyme like NAD+/NADP+ as an electron acceptor to catalyze the oxidation-reduction reaction. Alcohol dehydrogenase enzymes convert alcohol into aldehydes or ketones. Other aromatic dehydrogenases reported include naphthalene dihydrodiol dehydrogenase, polyethylene glycol dehydrogenase, benzyl alcohol dehydrogenase, and others [35]. Previously, bacterial cell-free extracts digest the industrially generated xenobiotics of various molecular weights, and the polyethylene glycol dehydrogenase activity was detected [36]. Similarly, another dehydrogenase, dye-linked polypropene glycol dehydrogenase in the periplasm or membrane of Stenotrophomonas maltophilia, is energetic in high-molecular-weight PPG degradation, whereas a cytoplasm-located enzyme was found to be active in hydrolyzing low-molecular-weight composite [37]. In a recent study, a novel dehydrogenase, 17β-hydroxysteroid dehydrogenase (17β-HSDx) present in Rhodococcus sp. P14, showed better activity in steroid bioremediation [38]. In previous studies, Rhodococcus sp. was originally involved in the degradation of various polycyclic aromatic hydrocarbons.
Biochemistry
Published in Ronald Fayer, Lihua Xiao, Cryptosporidium and Cryptosporidiosis, 2007
Pyruvate may be converted to acetyl-CoA by a bifunctional pyruvate, pyruvate:NADP+ oxidoreductase (PNO), which contains a pyruvate-ferredoxin oxidoreductase (PFO) domain and an NADPH-cytochrome P450 reductase domain (CPR) (Rotte et al., 2001). The architecture of PNO is unique to Cryptosporidium, as it is not present in any other apicomplexans examined so far, but found only in a distant free-living protist, Euglena gracilis (Rotte et al., 2001). Whereas Euglena PNO apparently contains a signal peptide sequence and is localized in the mitochondria, CpPNO is found in the cytosol (Ctrnacta et al., 2006). Acetyl-CoA can be converted by acetyl-CoA carboxylase (ACC) to malonyl-CoA, which serves as the building block in synthesizing fatty acids and polyketides. This parasite possesses only one cytosolic ACC, lacking the plastid ortholog found in Toxoplasma and Plasmodium (Jelenska et al., 2001, 2002; Gornicki, 2003). At least two organic end products can be formed from acetyl-CoA, including acetate by an acetate-CoA ligase (AceCL, also referred to as acetyl-CoA synthetase), in which an extra ATP molecule can be generated from AMP and PPi, and ethanol, by a bifunctional type E alcohol dehydrogenase (adhE) that first makes aldehyde and then ethanol. Ethanol may also be produced from pyruvate by pyruvate decarboxylase (PDC) coupled with a monofunctional ADH1. Pyruvate may also be converted to lactate by lactate dehydrogenase (LDH).
Construction of Enzyme Biosensors Based on a Commercial Glucose Sensor Platform
Published in Krzysztof Iniewski, Biological and Medical Sensor Technologies, 2017
Here, an amperometric biosensor for PGM activity with a bienzyme screen-printed biosensor is described. As shown in Figure 6.7, the principle is as follows: PGM (EC 5.4.2.2, from rabbit muscle, Sigma) converts glucose-1-phosphate to glucose-6-phosphate. Glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49, from Leuconostoc mesenteroides, Sigma) catalyzes the specific dehydrogenation of glucose-6-phosphate by consuming NAD+. The product “NADH” initiates the irreversible decarboxylation and the hydroxylation of salicylate by salicylate hydroxylase (SHL, EC 1.14.13.1, from Pseudomonas sp., GDS Technology Inc., Elkhart, IN) in the presence of oxygen to produce catechol, which results in a detectable signal due to its oxidation at the working electrode.
Biochemical pathways and associated microbial process of di-2-ethyl hexyl phthalate (DEHP) enhanced degradation by the immobilization technique in sequencing batch reactor
Published in Environmental Technology, 2022
Jia Chen, Siqiao Yang, Ke Zhang, Wei Chen, You Mo, Lin Li
The dehydrogenase can transfer the hydrogen atoms of the organic substrate to a specific hydrogen acceptor. Therefore, dehydrogenase activity (DHA) reflects the amount of microorganisms and their ability to metabolize organic substances. The microbial samples in three SBRs were collected at regular intervals, and the results are shown in Figure 5. The proportion of the total dehydrogenase activity (Dt) and substrate dehydrogenase activity (Ds) was higher than that of the endogenous respiration dehydrogenase activity (De) in all reactors. As the reactor operated, Dt and Ds gradually increased. In the first 10 days, Dt and Ds in CK were similar to T1. During the whole experiment period, Dt and Ds of T2 were higher than CK and T1, suggesting the application of the immobilization technique had a profound impact on the metabolic activity of microbes in SBRs.
Overview of biological mechanisms of human carcinogens
Published in Journal of Toxicology and Environmental Health, Part B, 2019
Nicholas Birkett, Mustafa Al-Zoughool, Michael Bird, Robert A. Baan, Jan Zielinski, Daniel Krewski
Ethanol is metabolized to acetaldehyde by three major pathways: the alcohol dehydrogenase (ADH) pathway, the microsomal ethanol oxidizing cytochrome P450 (CYP) pathway, and the catalase-H2O2 system. Acetaldehyde, to which many deleterious effects of ethanol can be attributed, is oxidized to acetate primarily by aldehyde dehydrogenases (ALDHs). Over the past decade, epidemiological evidence of enhanced cancer risks among heterozygous carriers of the inactive ALDH enzyme has become much stronger, in particular for esophageal cancer: practically all studies conducted in East-Asian populations who consumed alcoholic beverages show significantly increased odds ratios for carriers of the inactive ALDH allele. In addition, several studies have demonstrated associations between the polymorphism of ADH1B and upper aero-digestive tract cancers, which have been explained either by more active ADH producing more acetaldehyde or by less active ALDH causing prolonged exposure to lower levels of ethanol-derived acetaldehyde. These data imply that acetaldehyde is the key compound in the development of cancers of the esophagus and other upper aero-digestive tract cancers associated with alcoholic beverage consumption
Comparative proteomic analysis revealed the metabolic mechanism of excessive exopolysaccharide synthesis by Bacillus mucilaginosus under CaCO3 addition
Published in Preparative Biochemistry & Biotechnology, 2019
Hongyu Xu, Zhiwen Zhang, Hui Li, Yujie Yan, Jinsong Shi, Zhenghong Xu
Glucose-6-phosphate isomerase (Pgi), a second glycolytic enzyme, catalyzed the reversible aldose–ketose isomerization of glucose-6-phosphate to fructose 6-phosphate. This enzyme is also an enzymatic link between glycolysis and the pentose phosphate pathway.[27] 6-Phosphofructokinase (PfkA) was believed to be the most important element for the control of glycolytic flux. This enzyme catalyzes a physiologically reversible interconversion of fructose-6-phosphate and fructose-1,6-bisphosphate.[28] Aconitate hydratase (Acn), which transforms citrate to isocitrate, was the first step of the TCA cycle.[29] Glucose-6-phosphate dehydrogenase (G6PD) directed glucose-6-phosphate into the pentose phosphate pathway and played a pivotal role in cell function.[30] In this study, we found that all the four enzymes were down-regulated with CaCO3 addition and created a decreased carbon flux toward the growth of cells.