scholarly journals Compound I Is the Reactive Intermediate in the First Monooxygenation Step during Conversion of Cholesterol to Pregnenolone by Cytochrome P450scc: EPR/ENDOR/Cryoreduction/Annealing Studies

2012 ◽  
Vol 134 (41) ◽  
pp. 17149-17156 ◽  
Author(s):  
Roman Davydov ◽  
Andrey A. Gilep ◽  
Natallia V. Strushkevich ◽  
Sergey A. Usanov ◽  
Brian M. Hoffman
Keyword(s):  
Reactive Intermediate ◽  
Compound I ◽  
Cytochrome P450scc

Activation of cytochrome c to a peroxidase compound I-type intermediate by H2O2: relevance to redox signalling in apoptosis

2004 ◽  
Vol 71 ◽  
pp. 97-106 ◽  
Author(s):  
Mark Burkitt ◽  
Clare Jones ◽  
Andrew Lawrence ◽  
Peter Wardman
Keyword(s):  
Cytochrome C ◽  
Hydroxyl Radical ◽  
Redox Regulation ◽  
Chemotherapeutic Agents ◽  
Tyrosyl Radical ◽  
Compound I ◽  
Definitive Evidence ◽  
Enhanced Production ◽  
Physico Chemical

The release of cytochrome c from mitochondria during apoptosis results in the enhanced production of superoxide radicals, which are converted to H2O2 by Mn-superoxide dismutase. We have been concerned with the role of cytochrome c/H2O2 in the induction of oxidative stress during apoptosis. Our initial studies showed that cytochrome c is a potent catalyst of 2′,7′-dichlorofluorescin oxidation, thereby explaining the increased rate of production of the fluorophore 2′,7′-dichlorofluorescein in apoptotic cells. Although it has been speculated that the oxidizing species may be a ferryl-haem intermediate, no definitive evidence for the formation of such a species has been reported. Alternatively, it is possible that the hydroxyl radical may be generated, as seen in the reaction of certain iron chelates with H2O2. By examining the effects of radical scavengers on 2′,7′-dichlorofluorescin oxidation by cytochrome c/H2O2, together with complementary EPR studies, we have demonstrated that the hydroxyl radical is not generated. Our findings point, instead, to the formation of a peroxidase compound I species, with one oxidizing equivalent present as an oxo-ferryl haem intermediate and the other as the tyrosyl radical identified by Barr and colleagues [Barr, Gunther, Deterding, Tomer and Mason (1996) J. Biol. Chem. 271, 15498-15503]. Studies with spin traps indicated that the oxo-ferryl haem is the active oxidant. These findings provide a physico-chemical basis for the redox changes that occur during apoptosis. Excessive changes (possibly catalysed by cytochrome c) may have implications for the redox regulation of cell death, including the sensitivity of tumour cells to chemotherapeutic agents.

Structural Study of a new Compound Based on Acid 1,4-Cyclohexanedicarboxylic (1,4-CDC)

2010 ◽  
Vol 6 (1) ◽  
pp. 891-896
Author(s):  
Manel Halouani ◽  
M. Dammak ◽  
N. Audebrand ◽  
L. Ktari
Keyword(s):  
Aqueous Solution ◽  
Water Molecules ◽  
Carboxyl Group ◽  
X Ray Diffraction ◽  
Compound I ◽  
Unit Cell Parameters ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Parameters ◽  
Cyclohexanedicarboxylic Acid

One nickel 1,4-cyclohexanedicarboxylate coordination polymers, Ni2 [(O10C6H4)(COO)2].2H2O  (I), was hydrothermally synthesized from an aqueous solution of Ni (NO3)2.6H2O, (1,4-CDC) (1,4-CDC = 1,4-cyclohexanedicarboxylic acid) and tetramethylammonium nitrate. Compound (I) crystallizes in the monoclinic system with the C2/m space group. The unit cell parameters are a = 20.1160 (16) Å, b = 9.9387 (10) Å, c = 6.3672 (6) Å, β = 97.007 (3) (°), V= 1263.5 (2) (Å3) and Dx= 1.751g/cm3. The refinement converged into R= 0.036 and RW = 0.092. The structure, determined by single crystal X-ray diffraction, consists of two nickel atoms Ni (1) and Ni (2). Lots of ways of which is surrounded by six oxygen atoms, a carboxyl group and two water molecules.

Synthesis and Characterization of New Zinc Phthalocyanine - Dodecenyl Succinic Anhydride Benzoic Groups

2020 ◽  
Vol 17 (6) ◽  
pp. 488-495
Author(s):  
Hussein Ali Al-Bahrani ◽  
Mohanad Mousa Kareem ◽  
Abdul Amir Kadhum ◽  
Nour A. Alrazzak
Keyword(s):  
Salicylic Acid ◽  
Succinic Anhydride ◽  
Zinc Phthalocyanine ◽  
Central Metal ◽  
Target Compound ◽  
Compound I ◽  
Metal Phthalocyanines ◽  
Metal Atoms ◽  
Amino Salicylic Acid

Background: The phthalocyanines a series of compounds involves four iso-indole units linked by aza nitrogen atoms bonded with metal atoms that are normally located in the center a phthalocyanines ring. Some of the central metal-phthalocyanines can be excited by ultraviolet light and emit a fluorescence in far-red region. Objective: To synthesize a derivative of phthalocyanines namely 4,4',4' '-tri-(dodecenyl succinic anhydride)- 4' ' '-(5-amino salicylic acid) zinc phthalocyanine with a zinc central metal. Materials and Methods: The reaction of 4- nitro Phthalonitrile and 4- amino Phthalonitrile with ZnCl2 in the presence of dimethyl amino ethanol afforded 4,4',4' '-triamino-4' ' '-nitro zinc phthalocyanine. This product reacted with 5-amino salicylic acid to yield tetra-(5-amino salicylic acid) zinc phthalocyanine. A dodecenyl succinic anhydride was added on the amine group of benzoic rings to afford 4,4',4' '-tri-(dodecenyl succinic anhydride)-4' ' '-(5-amino salicylic acid) zinc phthalocyanine(I), the target compound. Results and Discussion: Compound I is successfully synthesized with a yield of 72% from tetra-(5-amino salicylic acid) zinc phthalocyanine with dodecenyl succinic anhydride. Conclusion: The newly synthesized molecule of 4,4',4' '-tri-(dodecenyl succinic anhydride)-4' ' '-(5-amino salicylic acid) zinc phthalocyanine (I), tetra-(5-amino salicylic acid) zinc phthalocyanine(E) and 4,4',4' '- triamino-4' ' '-nitro zinc phthalocyanine (S). The reaction of 4- nitro Phthalonitrile and 4- amino and the structure of compound I is confirmed and its formation was proven.

Pyrrolizines as Potential Anticancer Agents: Design, Synthesis, Caspase-3 activation and Micronucleus (MN) Induction

2019 ◽  
Vol 18 (15) ◽  
pp. 2124-2130
Author(s):  
Amany Belal
Keyword(s):  
Cancer Cells ◽  
Cell Lines ◽  
Anticancer Agents ◽  
Caspase 3 ◽  
Assay Method ◽  
Breast Adenocarcinoma ◽  
Compound I ◽  
Design Synthesis ◽  
Ic50 Values ◽  
New Compounds

Background: For further exploration of the promising pyrrolizine scaffold and in continuation of our previous work, that proved the potential anticancer activity of the hit compound I, a new series of pyrrolizines 2-5 and 7-9 were designed and synthesized. Methods: Structures of the new compounds were confirmed by IR, 1H-NMR, 13C-NMR and elemental analysis. Antitumor activity for the prepared compounds against human breast adenocarcinoma (MCF-7), liver (HEPG2) and colon (HCT116) cancer cell lines was evaluated using SRB assay method. Result: Compounds 2, 3 and 5 were the most potent on colon cancer cells, their IC50 values were less than 5 µM. Compounds 2, 3 and 8 were the most potent on liver cancer cells, their IC50 values were less than 10 µM. As for MCF7, compounds 2, 7, 8 and 9 were the most active with IC50 values less than 10 µM. We can conclude that combining pyrrolizine scaffold with urea gave abroad spectrum anticancer agent 2 against the three tested cell lines. Micronucleus assays showed that compounds 2, 3, 8 are mutagenic and can induce apoptosis. In addition, caspase-3 activation was evaluated and compound 2 showed increase in the level of caspase-3 (9 folds) followed by 3 (8.28 folds) then 8 (7.89 folds). Conclusion: The obtained results encourage considering these three compounds as novel anticancer prototypes.

Mechanism of the propagation step in the anionic polymerization of styrene

1980 ◽  
Vol 45 (4) ◽  
pp. 1047-1055 ◽  
Author(s):  
Miroslav Kašpar ◽  
Jiří Trekoval
Keyword(s):  
Experimental Data ◽  
Induction Period ◽  
Anionic Polymerization ◽  
Reactive Intermediate ◽  
Coordination Polymerization ◽  
Kinetic Dependence ◽  
Mathematical Solution ◽  
Slow Reaction

The paper is dealing with an investigation of the kinetic dependence of the propagation step in the anionic coordination polymerization of styrene in benzene at 303 K with "living" oligostyryllithium as initiator at the onset of the reaction. A short but distinct induction period was found, indicating a preceding slow reaction leading to the formation of a reactive intermediate, which behaves as the initiator of the reaction. Using results obtained in the first paper of this series, a new mechanism of propagation has been suggested, the mathematical solution of which is correlated with experimental data.

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