Stereochemically correct catalytic site on cyclodextrin resulting in a better enzyme model

1975 ◽  
Vol 97 (15) ◽  
pp. 4432-4434 ◽  
Author(s):  
Yoshio Iwakura ◽  
Keikichi Uno ◽  
Fujio Toda ◽  
Shigeharu Onozuka ◽  
Kenjiro Hattori ◽  
...  
Keyword(s):  
Catalytic Site ◽  
Enzyme Model

How feasible is the reversible S-dissociation mechanism for the activation of FeMo-co, the catalytic site of nitrogenase?

2019 ◽  
Vol 48 (4) ◽  
pp. 1251-1262 ◽  
Author(s):  
Ian Dance
Keyword(s):  
Coordination Chemistry ◽  
Catalytic Site ◽  
Dissociation Mechanism ◽  
Enzyme Model

Computations with a large enzyme model describe the coordination chemistry and protein involvement that could support the proposed dissociation of S2B from FeMo-co as part of the mechanism of nitrogenase.

A Peptide Dendrimer Enzyme Model with a Single Catalytic Site at the Core

2007 ◽  
Vol 129 (43) ◽  
pp. 13238-13246 ◽  
Author(s):  
Sacha Javor ◽  
Estelle Delort ◽  
Tamis Darbre ◽  
Jean-Louis Reymond
Keyword(s):  
Catalytic Site ◽  
The Core ◽  
Enzyme Model ◽  
Peptide Dendrimer

ChemInform Abstract: THE STEREOCHEMICALLY CORRECT CATALYTIC SITE ON CYCLODEXTRIN RESULTING IN A BETTER ENZYME MODEL

1975 ◽  
Vol 6 (41) ◽  
pp. no-no
Author(s):  
YOSHIO IWAKURA ◽  
KEIKICHI UNO ◽  
FUJIO TODA ◽  
SHIGEHARU ONOZUKA ◽  
KENJIRO HATTORI ◽  
...  
Keyword(s):  
Catalytic Site ◽  
Enzyme Model

Dual-Function, Light Switchable Cobalt Catalysis via Active Site Metamorphosis

2019 ◽  
Author(s):  
Enrico Bergamaschi ◽  
Frédéric Beltran ◽  
Christopher Teskey
Keyword(s):  
Visible Light ◽  
Active Site ◽  
Catalytic Site ◽  
Dual Function ◽  
Catalytic Systems ◽  
Hydride Complex ◽  
Dual Functional ◽  
Multiple Processes ◽  
Olefin Migration

<p></p><p></p><p>Switchable catalysis offers opportunities to control the rate or selectivity of a reaction <i>via</i> a stimulus such as pH or light. However, few examples of switchable catalytic systems that can facilitate multiple processes exist. Here we report a rare example of such dual-functional, switchable catalysis. Featuring an easily prepared, bench-stable cobalt(I) hydride complex in conjunction with pinacolborane, we can completely alter the reaction outcome between two widely employed transformations – olefin migration and hydroboration – with visible light as the sole trigger. This dichotomy arises from ligand photodissociation which leads to metamorphosis of the active catalytic site, resulting in divergent mechanistic pathways.</p><p></p><p></p>

α-Glucosidase Inhibition, Antioxidant and Docking Studies of Hydroxycoumarins and their Mono and Bis O-alkylated/acetylated Analogs

2018 ◽  
Vol 15 (2) ◽  
pp. 127-135 ◽  
Author(s):  
Parvesh Singh ◽  
Nomandla Ngcoya ◽  
Ramgopal Mopuri ◽  
Nagaraju Kerru ◽  
Neha Manhas ◽  
...  
Keyword(s):  
In Silico ◽  
Biological Activities ◽  
Wide Spectrum ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Catalytic Site ◽  
Docking Simulations ◽  
In Silico Docking ◽  
Anti Oxidant

Background: Diabetes Mellitus (DM) is a complex metabolic disease illustrated by abnormally high levels of plasma glucose or hyperglycaemia. Accordingly, several α-glucosidase inhibitors have been developed for the treatment of diabetes and other degenerative disorders. While, a coumarin ring has the privilege to represent numerous natural and synthetic compounds with a wide spectrum of biological activities e.g. anti-cancer, anti-HIV, anti-viral, anti-malarial, anti-microbial, anti-convulsant, anti-hypertensive properties. Besides this, coumarins have also shown potential to inhibit α-glucosidase leading to a generation of new promising antidiabetic agents. However, the testing of O-substituted coumarins for α-glucosidase inhibition has evaded the attention of medicinal chemists. Methods: For O-alkylation/acetylation reactions, the hydroxyl coumarins (A-B) initially activated by K2CO3 in dry DMF were reacted with variedly substituted haloalkanes at room temperature under nitrogen. The synthesized compounds were tested for their α-glucosidase (from Saccharomyces cerevisiae) inhibitory activity and anti-oxidant activity using DPPH radical scavenging activity. In silico docking simulations were conducted using CDocker module in DS (Accelrys) to explore the binding modes of the representative compounds in the catalytic site of α-glucosidase. Results: All the coumarin analogues (A1, B1, A2-A10, B2-B8) including their precursors (A-B) were evaluated for their in vitro α-glucosidase inhibition using acarbose as a standard inhibitor. All the mono O-alkylated coumarins (except A1) showed significant (p <0.05) α-glucosidase inhibition relative to the hydroxyl coumarin (A) with IC50 values ranging between 11.084±0.117 to 145.24± 29.22 µg/mL. Compound 7-(benzyloxy)-4, 5-dimethyl-2H-chromen-2-one (A9) bearing a benzyl group (Ph-CH2-) at position 7 showed a remarkable (p <0.05) increase in the activity (IC50 = 11.084±0.117 µg/mL), almost four-fold more than acarbose (IC50 = 40.578±5.999 µg/mL). The introduction of –NO2 group dramatically improved the anti-oxidant activity of coumarin, while the O-alkylation/acetylation decreased the activity. Conclusion: The present study describes the synthesis of functionalized coumarins and their evaluation for α-glucosidase inhibition and antioxidant activity under in vitro conditions. Based on IC50 data, the mono O-alkylated coumarins were observed to be stronger inhibitors of α-glucosidase with respect to their bis O-alkylated analogues. Coumarin (A9) bearing O-benzyloxy group displayed the strongest α-glucosidase inhibition, even higher than the standard inhibitor acarbose. The coumarin (A10) bearing –NO2 group showed the highest anti-oxidant activity amongst the synthesized compounds, almost comparable to the ascorbic acid. Finally, in silico docking simulations revealed the role of hydrogen bonding and hydrophobic forces in locking the compounds in catalytic site of α-glucosidase.

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