What Kinds of Ferryl Species Exist for Compound II of Chloroperoxidase? A Dialog of Theory with Experiment

2009 ◽  
Vol 113 (22) ◽  
pp. 7912-7917 ◽  
Author(s):  
Wenzhen Lai ◽  
Hui Chen ◽  
Sason Shaik
Keyword(s):  
2006 ◽  
Vol 128 (18) ◽  
pp. 6147-6153 ◽  
Author(s):  
Kari L. Stone ◽  
Lee M. Hoffart ◽  
Rachel K. Behan ◽  
Carsten Krebs ◽  
Michael T. Green
Keyword(s):  

2001 ◽  
Vol 390 (2) ◽  
pp. 304-308 ◽  
Author(s):  
Walleska De Jesús-Bonilla ◽  
José E. Cortés-Figueroa ◽  
Fernando A. Souto-Bachiller ◽  
Lolita Rodríguez ◽  
Juan López-Garriga

2019 ◽  
Vol 22 (8) ◽  
pp. 570-576
Author(s):  
Maryam Shokrollahi ◽  
Marjaneh Samadizadeh ◽  
Mohsen Khalili ◽  
Seyed A. Sobhanian ◽  
Abbas Ahmadi

Background: Phencyclidine (PCP, I) is a synthetic drug with remarkable physiological properties. PCP and its analogues exert many pharmacological activities and interact with some neurotransmitter systems in the central nervous system like particular affinity for PCP sites in NMDA receptors or dopamine uptake blocking or even both. Aim and Objective: The following research, methyl group with electron-donating and dipole moment characters was added in different positions of phenyl ring along with the substitution of benzylamine (with many pharmacological effects) instead of piperidine ring of I to produce new compounds (II-V) of this family with more analgesic activities. Materials and Methods: Analgesic activities of these new compounds were measured by tail immersion and formalin tests for acute and chronic pains, respectively. Also, the outcomes were compared with control and PCP (10 mg/kg) groups. Results: The results indicate that compounds III, IV, and V have more acute and chronic antinociceptive effects than PCP and compound II which may be concerned with more antagonizing activities of these new painkillers for the blockage of dopamine reuptake as well as high affinity for NMDA receptors PCP binding site. Conclusion: It can be concluded that the benzylamine derivative of phencyclidine with a methyl group on the benzyl position on phenyl ring (V) is a more appropriate candidate to reduce acute and chronic (thermal and chemical) pains compared to other substituted phenyl analogs (II-IV) and PCP.


2021 ◽  
Vol 22 (5) ◽  
pp. 2629
Author(s):  
Dolores Linde ◽  
Iván Ayuso-Fernández ◽  
Marcos Laloux ◽  
José E. Aguiar-Cervera ◽  
Antonio L. de Lacey ◽  
...  

We aim to clarify the ligninolytic capabilities of dye-decolorizing peroxidases (DyPs) from bacteria and fungi, compared to fungal lignin peroxidase (LiP) and versatile peroxidase (VP). With this purpose, DyPs from Amycolatopsis sp., Thermomonospora curvata, and Auricularia auricula-judae, VP from Pleurotus eryngii, and LiP from Phanerochaete chrysosporium were produced, and their kinetic constants and reduction potentials determined. Sharp differences were found in the oxidation of nonphenolic simple (veratryl alcohol, VA) and dimeric (veratrylglycerol-β- guaiacyl ether, VGE) lignin model compounds, with LiP showing the highest catalytic efficiencies (around 15 and 200 s−1·mM−1 for VGE and VA, respectively), while the efficiency of the A. auricula-judae DyP was 1–3 orders of magnitude lower, and no activity was detected with the bacterial DyPs. VP and LiP also showed the highest reduction potential (1.28–1.33 V) in the rate-limiting step of the catalytic cycle (i.e., compound-II reduction to resting enzyme), estimated by stopped-flow measurements at the equilibrium, while the T. curvata DyP showed the lowest value (1.23 V). We conclude that, when using realistic enzyme doses, only fungal LiP and VP, and in much lower extent fungal DyP, oxidize nonphenolic aromatics and, therefore, have the capability to act on the main moiety of the native lignin macromolecule.


Author(s):  
Hanna Kwon ◽  
Jaswir Basran ◽  
Chinar Pathak ◽  
Mahdi Hussain ◽  
Samuel L Freeman ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 603
Author(s):  
Prashanth Sandineni ◽  
Hooman Yaghoobnejad Asl ◽  
Weiguo Zhang ◽  
P. Shiv Halasyamani ◽  
Kartik Ghosh ◽  
...  

Herein, we report the syntheses of two lithium-vanadium oxide-fluoride compounds crystallized from the same reaction mixture through a time variation experiment. A low temperature hydrothermal route employing a viscous paste of V2O5, oxalic acid, LiF, and HF allowed the crystallization of one metastable phase initially, Li2VO0.55(H2O)0.45F5⋅2H2O (I), which on prolonged heating transforms to a chemically similar yet structurally different phase, Li3VOF5 (II). Compound I crystallizes in centrosymmetric space group, I2/a with a = 6.052(3), b = 7.928(4), c = 12.461(6) Å, and β = 103.99(2)°, while compound II crystallizes in a non-centrosymmetric (NCS) space group, Pna21 with a = 5.1173(2), b = 8.612(3), c = 9.346(3) Å. Synthesis of NCS crystals are highly sought after in solid-state chemistry for their second-harmonic-generation (SHG) response and compound II exhibits SHG activity albeit non-phase-matchable. In this article, we also describe their magnetic properties which helped in unambiguous assignment of mixed valency of V (+4/+5) for Li2VO0.55(H2O)0.45F5⋅2H2O (I) and +4 valency of V for Li3VOF5 (II).


1993 ◽  
Vol 290 (1) ◽  
pp. 289-296 ◽  
Author(s):  
G W Mellor ◽  
E W Thomas ◽  
C M Topham ◽  
K Brocklehurst

1. A new thiol-specific reactivity probe 4,4′-dipyrimidyl disulphide [compound (VII), m.p. 110 degrees C, pKa of its monohydronated form 0.91] was synthesized and used to resolve the ambiguity of interpretation of the behaviour of papain (EC 3.4.22.2) in alkaline media known to depend to varying extents on two ionizations with pKa values approx. 8.0-8.5 and > or = 9.5 respectively. 2. A new extensive pH-second-order rate constant (k) data set for the reaction of papain with 2-(acetamido)-ethyl 2′-pyridyl disulphide (IV) demonstrated the existence of a striking rate maximum at pH approx. 4, the independence of k around pH 8 and the increase in k with increase in pH across a pKa value of 10.0, behaviour similar to that of other 2-pyridyl disulphides (R-S-S-2-Py) that lack key substrate-like binding sites in R. 3. Although the simplest interpretation of the pKa value of 10.0 assigns it to the formation of (Cys-25)-S-/(His-159)-Im from the ion-pair state of the papain catalytic site, another interpretation may be conceived in which this pKa value is assigned to another group remote from the catalytic site, the state of ionization of which modulates catalytic-site behaviour. This alternative assignment is shown to require compensating effects in the pH region around 8 such that the formation of (Cys-25)-S-/(His-159)-Im across pKa 8.0-8.5 is without net kinetic effect in the reactions of simple 2-pyridyl disulphides such as compound (IV) and 2,2′-dipyridyl disulphide (II). 4. The lower basicity of compound (VII) relative to that of compound (II) (pKa 2.45) was predicted to diminish or abolish the compensation postulated as a possibility in reactions of 2-pyridyl disulphides because of the decreased effectiveness of reaction via a (His-159)-Im+H-assisted transition state. The characteristics of the pH-dependence of the reaction of papain with compound (VII) which are quite different from those for its reaction with compound (II) support both this prediction and the alternative assignment with a value of 8.3 for the pKa of the formation of (Cys-25)-S-/(His-159)-Im. 5. Evidence that the behaviour of papain towards both substrates and some substrate-derived time-dependent inhibitors is determined not only by the loss of the (Cys-25)-S-/(His-159)-Im+H ion-pair state by dehydronation with pKa 8.3 but also by another ionization of pKa approx. 10.0 is briefly discussed.


Author(s):  
Olha Sereda ◽  
Helen Stoeckli-Evans

The title compounds,catena-poly[[[bis[(R)-propane-1,2-diamine-κ2N,N′]copper(II)]-μ-cyanido-κ2N:C-[tris(cyanido-κC)(nitroso-κN)iron(III)]-μ-cyanido-κ2C:N] monohydrate], {[Cu(Lpn)2][Fe(CN)5(NO)]·H2O}n, (I), and poly[[hexa-μ-cyanido-κ12C:N-hexacyanido-κ6C-hexakis[(R)-propane-1,2-diamine-κ2N,N′]dichromium(III)tricopper(II)] pentahydrate], {[Cu(Lpn)2]3[Cr(CN)6]2·5H2O}n, (II) [where Lpn = (R)-propane-1,2-diamine, C3H10N2], are new chiral cyanide-bridged bimetallic coordination polymers. The asymmetric unit of compound (I) is composed of two independent cation–anion units of {[Cu(Lpn)2][Fe(CN)5)(NO)]} and two water molecules. The FeIIIatoms have distorted octahedral geometries, while the CuIIatoms can be considered to be pentacoordinate. In the crystal, however, the units align to form zigzag cyanide-bridged chains propagating along [101]. Hence, the CuIIatoms have distorted octahedral coordination spheres with extremely long semicoordination Cu—N(cyanido) bridging bonds. The chains are linked by O—H...N and N—H...N hydrogen bonds, forming two-dimensional networks parallel to (010), and the networks are linkedviaN—H...O and N—H...N hydrogen bonds, forming a three-dimensional framework. Compound (II) is a two-dimensional cyanide-bridged coordination polymer. The asymmetric unit is composed of two chiral {[Cu(Lpn)2][Cr(CN)6]}−anions bridged by a chiral [Cu(Lpn)2]2+cation and five water molecules of crystallization. Both the CrIIIatoms and the central CuIIatom have distorted octahedral geometries. The coordination spheres of the outer CuIIatoms of the asymmetric unit can be considered to be pentacoordinate. In the crystal, these units are bridged by long semicoordination Cu—N(cyanide) bridging bonds forming a two-dimensional network, hence these CuIIatoms now have distorted octahedral geometries. The networks, which lie parallel to (10-1), are linkedviaO—H...O, O—H...N, N—H...O and N—H...N hydrogen bonds involving all five non-coordinating water molecules, the cyanide N atoms and the NH2groups of the Lpn ligands, forming a three-dimensional framework.


2014 ◽  
Vol 48 (11) ◽  
pp. 1334-1341 ◽  
Author(s):  
J. Krych ◽  
J. L. Gebicki ◽  
L. Gebicka

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