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Biocatalysts: The Different Classes and Applications for Synthesis of APIs
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
These enzymes belonging to the class of lyase enzymes catalyze the formation of C–C bonds known from Organic Chemistry as the aldol-reaction. The aldolase-catalyzed reaction represents a reversible stereoselective addition of a nucleophile to an electrophile. In living cells, aldolases play a key role in degradation as well as in synthesis of carbohydrates and keto acids. Natural donors (see scheme below) of aldolases are dihydroxyacetone phosphate (DHAP), pyruvate and phosphoenol pyruvate (PEP), acetaldehyde and glycine. Several aldolases, among them KDPG and KDPGal aldolase, or N-acetyl neuraminic acid lyase (Walters and Toone, 2017; Stockwell et al., 2016) accept fluoropyruvate as an alternative donor substrate to pyruvate, a property used by Windle et al. (2017), to investigate the stereoselective synthesis of fluorinated compounds such as α-fluoro β-hydroxy carboxyl derivatives.
Tissue Engineering: overview of biochemical data and mechanical modeling
Published in Benjamin Loret, Fernando M. F. Simões, Biomechanical Aspects of Soft Tissues, 2017
Benjamin Loret, Fernando M. F. Simões
Glycolysis contains two phosphorylation steps: these steps which consist in transfering a phosphate group require two ATP4− moles for each mole of glucose, Fig. 20.2.3. Aldolase hydrolyzes fructose-1,6-biphosphate in two fragments that can be converted into one another. A subsequent product, 1,3-biphosphoglycerate, contains an anhydrous bond that is much exenergetic: its hydrolysis allows for formation of ATP4− in a next step. Next to oxidative phosphorylation and thiokinase in the Krebs cycle, the above 3-phosphoglycerate kinase and the final pyruvate kinase are the sole reactions that produce ATP4−.
Current State of Malaria Diagnosis: Conventional, Rapid, and Safety Diagnostic Methods
Published in Jyoti Ranjan Rout, Rout George Kerry, Abinash Dutta, Biotechnological Advances for Microbiology, Molecular Biology, and Nanotechnology, 2022
Barsa Baisalini Panda, Rupenangshu Kumar Hazra
For quick malaria diagnostic tests, aldolase enzymes are considered as targets which are recognized inside the glycolytic pathway of the malaria parasite. Citric acid cycle is not present in human malaria blood-stage metabolism; therefore, ATP generation fully depends on the glycolytic cycle. In this pathway, aldolase plays an important role as a key enzyme. In P. berghei that is, rodent malaria parasite, two glycolytic aldolase enzymes (aldo-1 and aldo-2) are used to examine the particular expression of aldolase isoenzymes. The aldo-1 was alike P. falciparum aldolase, while 13% sequence diversity was seen in aldo-2 (Meier et al., 1992). In the blood, asexual stages and sporozoite of malaria parasites were detected by aldo-1 and aldo-2 by using specific antibodies. Monoclonal antibodies created in contradiction of Plasmodium aldolase, which is pan-specific and with the combination of HRP-2 it has been used to identify 2 Plasmodium species that is, Pf and Pv in blood. The combined Pf/Pv immunochromatographic test (ICT Pf/Pv) was evaluated by Tjitra et al. (1999) and these were designed with capture stripes for both aldolase and HRP-2. They have reported that the negative predictive value and specificity were 98.2% and 94.8%, respectively, for the analysis of P. vivax but the positive predictive value of 50% and the overall sensitivity of 75% for P. vivax malaria were less than advisable in their study. The sensitivity was 96% for more than 500 parasites/µL (0.01% parasitemia), but for values lower than 500 parasites/µL was only 29%. In a study at Brisbane, Australia, 13 patients were detected as ill with malaria by the ICT Pf/Pv test. Eisen and Saul (2000) also displayed less sensitivity for the recognition of P. vivax when the parasite count was less than 500 parasites/µL (0.01% parasitemia). They explained that unlike the HRP2 line with Pf or Pv infection during treatment if the intensity of pan-specific line is declined, it means it became negative though it is positive for a considerable period.
Reactor and microreactor performance and kinetics of the aldol addition of dihydroxyacetone to benzyloxycarbonyl-N-3-aminopropanal catalyzed by D-fructose-6-phosphate aldolase variant A129G
Published in Chemical Engineering Communications, 2019
Martina Sudar, Zvjezdana Findrik, Anna Szekrenyi, Pere Clapés, Đurđa Vasić-Rački
In this work aldolase variant FSA A129G was investigated in the reaction of aldol addition of 2 to 1. The developed mathematical model was validated on independent set of experiments carried out in two reactors: batch reactor and microreactor. FSA A129G catalyzes successfully the reaction in both batch reactor and microreactor and similar residence/reaction time was needed to obtain maximum conversion of 1. The use of a microreactor did not have any beneficial effect on the reaction performance, but on the contrary, the enzyme showed a decrease in its activity at longer residence times in one type of microreactor (13 µl). On the other hand, FSA A129G was stable for 28 hours without any loss of activity in the batch reactor and hence, it was possible to carry out a repetitive batch reaction. Thus, it was concluded that the preferred reactor type for this reaction is the batch reactor. When comparing this enzyme with two previously investigated aldolase variants, FSA A129S and FSA A129S/A165G, regardless of the maximum reaction rates, its superior stability in the batch reactor makes it a better choice as a catalyst for the investigated aldol addition reaction.
Differential expression of hepatic genes with embryonic exposure to an environmentally relevant PCB mixture in Japanese quail (Coturnix japonica)
Published in Journal of Toxicology and Environmental Health, Part A, 2018
Meredith E. Bohannon, Tom E. Porter, Emma T. Lavoie, Mary Ann Ottinger
Of the four genes tested with qPCR, CYP1A5, and CYB5 are AhR-mediated genes (Head and Kennedy 2007; Helgason et al. 2010; Hervé et al. 2010; Ohtake et al. 2006). CYP1A5 was expected to be upregulated in response to AhR ligands such as PCB, as was also noted on the microarray. CYB5 is a protein involved in the large complex made up by CYP1 proteins, cytochrome b5-NADH reductase, and NADPH reductase (Wright and Welbourn 2002). ALDOB is a liver-specific fructose 1,6-bisphosphate aldolase; therefore, it is involved with glycolysis and gluconeogenesis (Droppelmann et al. 2015). This is consistent with a rise in expression of genes involved with metabolism in response to PCB exposure. Finally, GSTA is a Phase II antioxidative enzyme responsible for the conversion of reduced GSH to oxidized GSH as well as other activities such as peroxidation and isomerization (Sheehan et al. 2001), thereby furthering the hypothesis that PCB exposure may increase oxidative damage through enhanced metabolism (Schlezinger et al. 2006). However, there are no apparent reports that show an elevation in GSTA expression in particular, although several reports indicate an increase in glutathione S-transferase enzyme activity (Barhoumi et al. 1994; Morozov, Chiuko, and Brodskii 2012). Helgason et al. (2010) demonstrated a rise in glutathione S-transferase activity following PCB exposure. However, there are a number of studies that reported either no change in glutathione S-transferase expression or a decrease in expression (Morozov and Yurichenko 2016; Tian et al. 2012; Tomza-Marciniak et al. 2014). Therefore, data presented here are theoretically expected but experimentally surprising.
Effects of glycerol and glucose on docosahexaenoic acid synthesis in Aurantiochyrium limacinum SFD-1502 by transcriptome analysis
Published in Preparative Biochemistry & Biotechnology, 2023
Huaqiu Zhang, Xiangying Zhao, Chen Zhao, Jiaxiang Zhang, Yang Liu, Mingjing Yao, Jianjun Liu
Pyruvate is a precursor of acetyl-CoA and an end product of EMP pathway. Compared with glycerol, the pyruvate kinase (PK) using glucose as carbon source, which is the rate-limiting enzyme in the glycolytic pathway, was upregulated during the fermentation, especially was upregulated by 3-fold at 24 hr. Moreover, when cultured with glucose, the expression of fructose diphosphate aldolase (FBAld), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and 3-phosphoglycerate kinase (3PGK) which were also involved in glycolysis was obviously higher than cultured with glycerol. Therefore, it can be concluded that the EMP pathway was more active in the group glucose than in group glycerol.