Enzyme Inhibitors and Activators

Лопина, О.Д.

doi:10.5772/67248

Cited by 36 publications

(20 citation statements)

References 35 publications

(45 reference statements)

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“…Our previous work with Gd-based nanozymes showed that L-cysteine amino acid acts as a reversible inhibitor [ 51 , 52 ]. In that case, L-cysteine did not act as a catalyst poison but instead, it interacted with the nanozyme through a competitive inhibition process where there was a competition between L-cysteine and the peroxidase substrates to bind to the surface of the nanozyme.…”

Section: Resultsmentioning

confidence: 99%

L-Cysteine as an Irreversible Inhibitor of the Peroxidase-Mimic Catalytic Activity of 2-Dimensional Ni-Based Nanozymes

et al. 2021

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The ability to modulate the catalytic activity of inorganic nanozymes is of high interest. In particular, understanding the interactions of inhibitor molecules with nanozymes can bring them one step closer to the natural enzymes and has thus started to attract intense interest. To date, a few reversible inhibitors of the nanozyme activity have been reported. However, there are no reports of irreversible inhibitor molecules that can permanently inhibit the activity of nanozymes. In the current work, we show the ability of L-cysteine to act as an irreversible inhibitor to permanently block the nanozyme activity of 2-dimensional (2D) NiO nanosheets. Determination of the steady state kinetic parameters allowed us to obtain mechanistic insights into the catalytic inhibition process. Further, based on the irreversible catalytic inhibition capability of L-cysteine, we demonstrate a highly specific sensor for the detection of this biologically important molecule.

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Section: Resultsmentioning

confidence: 99%

L-Cysteine as an Irreversible Inhibitor of the Peroxidase-Mimic Catalytic Activity of 2-Dimensional Ni-Based Nanozymes

et al. 2021

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“…For the hydrolysis reaction, two further inhibition mechanisms are conceivable. On the one hand, parts of two substrate molecules could bind to the active center of the enzyme and thus form a dead-end ES 2 complex ( Lopina, 2017 ). The conformational flexibility of the 3′- and 5′-phosphate moieties observed for the alarmone species, which allows interaction with a broad spectrum of intracellular targets ( Steinchen and Bange, 2016 ), could facilitate this process.…”

Section: Discussionmentioning

confidence: 99%

Functional Characterization of a Small Alarmone Hydrolase in Corynebacterium glutamicum

et al. 2018

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The (pp)pGpp metabolism is an important component of bacterial physiology as it is involved in various stress responses and mechanisms of cell homeostasis, e.g., the regulation of growth. However, in order to better understand the (pp)pGpp associated regulation, it is crucial to study the molecular mechanisms of (pp)pGpp metabolism. In recent years, bioinformatic analyses of the RelA/SpoT homolog (RSH) superfamily have led to the discovery of small monofunctional RSH derivatives in addition to the well-known bifunctional Rel proteins. These are also referred to as small alarmone synthetases (SASs) or small alarmone hydrolases (SAHs). In this study, the ORF cg1485 from C. glutamicum was identified as a putative SAH encoding gene, based on a high similarity of the corresponding amino acid sequence with the (pp)pGpp hydrolysis domain. The characterization of its gene product, designated as RelHCg, represents the first functional investigation of a bacterial representative of the SAH subfamily. The predicted pyrophosphohydrolase activity was demonstrated in vivo by expression in two E. coli strains, characterized by different alarmone basal levels, as well as by in vitro analysis of the purified protein. During the assay-based analysis of hydrolysis activity in relation to the three known alarmone species, both RelHCg and the bifunctional RSH enzyme RelCg were found to exhibit a pronounced substrate inhibition for alarmone concentrations of more than 0.75 mM. This characteristic of (pp)pGpp hydrolases could be an important mechanism for realizing the bistable character of the (pp)pGpp metabolism between a (pp)pGpp basal level and stress-associated alarmone production. The deletion of relHCg caused only a minor effect on growth behavior in both wild-type background and deletion mutants with deletion of (pp)pGpp synthetases. Based on this observation, the protein is probably only present or active under specific environmental conditions. The independent loss of the corresponding gene in numerous representatives of the genus Corynebacterium, which was found by bioinformatic analyses, also supports this hypothesis. Furthermore, growth analysis of all possible deletion combinations of the three active C. glutamicum RSH genes revealed interesting functional relationships which will have to be investigated in more detail in the future.

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“…Thus, a metal dependency of this enzyme cannot be deduced safely at this point. The effects of EDTA could also result from an overall sensibility of the enzyme structure for changes in its environment (Bisswanger 2014;Robinson 2015;Lopina 2017). The negative effect of the anionic detergent SDS on the activities of all three novel agarases from M. elongatus PORT2 indicated their localization in the cell membrane.…”

Section: Discussionmentioning

confidence: 99%

Characterization and Modeling of Thermostable GH50 Agarases from Microbulbifer elongatus PORT2

Anggraeni

Ansorge‐Schumacher

2021

Mar Biotechnol

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Viewing the considerable potential of marine agar as a source for the sustainable production of energy as well as nature-derived pharmaceutics, this work investigated the catalytic activity of three novel GH50 agarases from the mesophilic marine bacterium Microbulbifer elongatus PORT2 isolated from Indonesian coastal seawaters. The GH50 agarases AgaA50, AgaB50, and AgaC50 were identified through genome analysis; the corresponding genes were cloned and expressed in Escherichia coli BL21 (DE3). All recombinant agarases hydrolyzed β-p-nitrophenyl galactopyranoside, indicating β-glycosidase characteristics. AgaA50 and AgaB50 were able to cleave diverse natural agar species derived from Indonesian agarophytes, indicating a promising tolerance of these enzymes for substrate modifications. All three GH50 agarases degraded agarose, albeit with remarkable diversity in their catalytic activity and mode of action. AgaA50 and AgaC50 exerted exolytic activity releasing differently sized neoagarobioses, while AgaB50 showed additional endolytic activity in dependence on the substrate size. Surprisingly, AgaA50 and AgaB50 revealed considerable thermostability, retaining over 75% activity after 1-h incubation at 50 °C. Considering the thermal properties of agar, this makes these enzymes promising candidates for industrial processing.

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Enzyme Inhibitors and Activators

Cited by 36 publications

References 35 publications

L-Cysteine as an Irreversible Inhibitor of the Peroxidase-Mimic Catalytic Activity of 2-Dimensional Ni-Based Nanozymes

L-Cysteine as an Irreversible Inhibitor of the Peroxidase-Mimic Catalytic Activity of 2-Dimensional Ni-Based Nanozymes

Functional Characterization of a Small Alarmone Hydrolase in Corynebacterium glutamicum

Characterization and Modeling of Thermostable GH50 Agarases from Microbulbifer elongatus PORT2

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