scholarly journals The Oxidation Cascade of a Rare Multifunctional P450 Enzyme Involved in Asperterpenoid A Biosynthesis

2021 ◽  
Vol 9 ◽  
Author(s):  
Hui-Yun Huang ◽  
Jia-Hua Huang ◽  
Yong-Heng Wang ◽  
Dan Hu ◽  
Yong-Jun Lu ◽  
...  
Keyword(s):  
Quantum Chemistry ◽  
Quantum Chemistry Calculation ◽  
Oxidation Reactions ◽  
Cytochrome P450 Enzymes ◽  
Key Factors ◽  
Transformant Strain ◽  
Quantum Chemistry Calculations ◽  
Wide Range ◽  
P450 Enzyme ◽  
Chemistry Calculation

The cytochrome P450 enzymes (P450s or CYPs) are heme-containing enzymes which catalyze a wide range of oxidation reactions in nature. In our previous study, a rare multifunctional P450 AstB was found, which can dually oxidize two methyl groups (C-19 and C-21) of preasperterpenoid A to asperterpenoid A with 3-carboxyl and 11-hydroxymethyl groups. However, the oxidation order of C-19 and C-21 catalyzed by AstB is unclear. In order to reveal this oxidation order, probable pathways catalyzed by AstB were proposed, and the oxidation order of C-19 and C-21 was obtained by quantum chemistry calculations. The potential intermediates (three new asperterpenoids D–F, 1–3) were obtained through the chemical investigation on the extract of the transformant strain and chemical conversions, which were used as the standards to detect their existences in the extract of the transformant strain with HPLC-MS. Combined with the quantum chemistry calculation and the HPLC-MS analysis, the catalyzed order of AstB in asperterpenoid A biosynthesis was revealed. Furthermore, the mPTPB inhibition of obtained asperterpenoids was evaluated, and the results showed that 3-carboxyl and the oxidation station of C-21 would be the key factors for mPTPB inhibition of asperterpenoids.

Theoretical Study on Thermal Hazardous Properties of C18H10O11 and C18H18O7 Organic Peroxides

2013 ◽  
Vol 787 ◽  
pp. 301-305
Author(s):  
Yun Bo He ◽  
Wei Wang ◽  
Shi Xiong Wang ◽  
Xiang Jun Yang ◽  
Hong Guo
Keyword(s):  
Molecular Structure ◽  
Thermal Decomposition ◽  
Quantum Chemistry ◽  
Organic Compounds ◽  
Theoretical Study ◽  
Organic Peroxides ◽  
Quantum Chemistry Calculation ◽  
The Past ◽  
Chemistry Calculation ◽  
The Stability

The thermal decomposition of organic peroxides are widely used as coagulant for organic compounds, however, its thermal hazardous characteristics have already caused serious accidents in chemical industries, which limited its application in much more strict conditions. Organic peroxides of C18H10O11 and C18H18O7 are two new candidates fitted for industrial explosive. However, as we best known there is little reports available on the geometry structure in the past decades. In this work, by means of quantum chemistry calculation, the relation of safety with molecular structure of C18H10O11 and C18H18O7 are discussed. The molecules with more activity O and the activity part more dispersedly exhibit higher stable, and the configuration has good safety. All the energy of molecule b is higher than that of molecule a. The stability of different configurations are 6a>7a>8a>9a>5a>1a>4a>3a=2a and 1b>7b>5b>6b>4b>2b>3b>8b, respectively, suggesting the structures of 6a,3a,2a,1b,8b exhibit high safety.

2-(3-Acylselenoureido)benzonitriles and 2-(3-Acylselenoureido)thiophene-3-carbonitriles. Preparation, Structure Elucidation, Cyclization and Retrocyclization Reactions

1999 ◽  
Vol 64 (10) ◽  
pp. 1673-1695 ◽  
Author(s):  
Jiří Šibor ◽  
Dalimil Žůrek ◽  
Radek Marek ◽  
Michal Kutý ◽  
Otakar Humpa ◽  
...  
Keyword(s):  
Quantum Chemistry ◽  
Ab Initio ◽  
Potassium Hydroxide ◽  
Potassium Hydroxide Solution ◽  
Quantum Chemistry Calculation ◽  
Potassium Salts ◽  
X Ray ◽  
Chemistry Calculation ◽  
Acid Cyclization

Synthesis of 2-(3-acylselenoureido)benzonitriles and 2-(3-acylselenoureido)thiophene- 3-carbonitriles 5a-5f by addition of 2-aminonitriles 4a-4c to benzoyl- or 2,2-dimethyl- propanoylisoselenocyanate and their cycloaddition reactions are described. Structures of compounds 5a-5f were supported by CIMS, FTIR, 1H, 13C, 77Se and 15N NMR spectra. The parameters of 15N and 77Se nuclei were obtained from inverse 1H-X 2D HMBC and GSQMBC correlation experiments at natural abundance. Structure of compound 5b was confirmed by X-ray analysis. The geometry of 5b was optimized by ab initio RHF/DZVP quantum chemistry calculation. A very good correlation between the calculation and experimental data was found. The geometry of 5e was optimized by ab initio DFT/VWN/DZVP quantum chemistry calculation. It was found that title compounds 5a-5f do not undergo isomerization to acylisoselenoureas, in contrast to analogous ester derivatives. Fused 6-imino-6H-1,3- selenazinium salts (chlorides 6a-6f, hydrogensulfates 7a-7f and tetrafluoroborates 8a-8f) were prepared by an acid cyclization of 5a-5f. It was found that neutralization of 6a-6f, 7a-7f and 8a-8f led to their retrocyclization to 5a-5f. Selenoureas 5a-5f with equimolar amounts of methanolic potassium hydroxide afforded potassium salts 9a-9f. Only the salts 9b, 9c, 9e and 9f of the thiophene series were isolated. Their heating in methanol solution led to deacylation of isoselenoureas 10b and 10c. The in situ prepared compounds 9a and 9d cyclized and deacylated to 4-aminoquinazoline-2-selenole 11a under the same conditions. The compounds 5a-5f and 10a-10c cyclized to fused 4-aminopyrimidine-2-selenols 11a, 11b and 4-aminopyrimidine-2-selenone 12c by boiling in methanolic potassium hydroxide solution.

Sign in / Sign up

Export Citation Format

Share Document