Stabilized Isoporphyrin Intermediates in the Inactivation of Horseradish Peroxidase by Alkylhydrazines

Ator, Mark A.; David, Shantha; Montellano, Paul R. Ortiz de

doi:10.1016/s0021-9258(18)60522-8

Cited by 44 publications

(21 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In fact, such a complex could be detrimental as the formation of a tightly bound substrate radical after oxidation might lead to enzyme inactivation. This is similar to what is seen with radical suicide substrates [31,32].…”

Section: Substrate Access Channelsupporting

confidence: 86%

The crystal structure of peanut peroxidase

et al. 1996

View full text Add to dashboard Cite

This is the first complete structure of a class III peroxidase and as such should serve as a model for other class III enzymes including the much-studied horseradish peroxidase. It may also aid in the interpretation of functional differences between the peroxidase classes. Ten helices conserved in class I and II peroxidases are also found in peanut peroxidase. Key residues of the heme environment and the location of two calcium ions are shared with class II peroxidases. Peanut peroxidase contains three unique helices, two of which contribute to the substrate access channel leading to the heme edge.

show abstract

Section: Substrate Access Channelsupporting

confidence: 86%

The crystal structure of peanut peroxidase

et al. 1996

View full text Add to dashboard Cite

show abstract

“…Hydrogen peroxide has a disadvantageous effect on enzyme stability which can inactivate the peroxidase [35] . The deactivation process of peroxidase in the enzyme‐catalyzed oxidation consists of two stages: the formation of compound III which is followed by the accumulation of irreversibly deactivated peroxidase [36] .…”

Section: Resultsmentioning

confidence: 99%

“…K 5 ×Y(1)×A 0 ×Y(1)×A 0 and K 7 ×Y(2)×B 0 ×Y(2)×B 0 represent the substrate inhibition items for H 2 O 2 and omeprazole thioether, respectively. As shown in Table 1, K 5 is high, indicating that H 2 O 2 has significant substrate inhibition on the enzymatic sulfoxidation, and in fact, H 2 O 2 is unfavorable for peroxidases [35,36] . On the contrary, K 7 is very small, meaning that the substrate inhibition of omeprazole thioether can be ignored.…”

Section: Resultsmentioning

confidence: 99%

Asymmetric Sulfoxidation of Thioether Catalyzed by Soybean Pod Shell Peroxidase to Form Enantiopure Sulfoxide in Water‐in‐Oil Microemulsions: A Kinetic Model

Deng

et al. 2021

Chemistry An Asian Journal

View full text Add to dashboard Cite

Esomeprazole with chiral sulfoxides structure is used to treat gastric ulcer disease. Soybean pod shell peroxidase (SPSP) is a peroxidase extracted from soybean pods shells which are one of the most abundant natural resources in the world. In the production of chiral sulfoxides catalyzed by SPSP, it is very important to establish the reaction kinetic model and explore the reaction mechanism for the development of the process, however, there is no report on the establishment of the model. Asymmetric sulfoxidation reactions catalyzed by SPSP in water‐in‐oil microemulsions were carried out, and the King‐Altman approach was used to establish a kinetic model. A yield of 91% and e.e. value of 96% for esomeprazole were obtained at the activity of SPSP of 3200 U ml−1 and 50 °C for 5 h. The mechanism with a two‐electron reduction of SPSP‐I is accompanied with a single‐electron transfer to SPSP‐I and nonenzymatic reactions, indicating that three concomitant sub‐mechanisms contribute to the asymmetric oxidation involving five enzymatic and two nonenzymatic reactions, which can represent the asymmetric sulfoxidation of organic sulfides to form enantiopure sulfoxides. With 5.44% of the average relative deviation, a kinetic model fitting experimental data was developed. The enzymatic reactions may follow ping‐pong mechanism with substrate inhibition of H2O2 and product inhibition of esomeprazole, while nonenzymatic reactions follow a power law. Those results indicate that SPSP with a lower cost and higher thermal stability may be used as an effective substitute for horseradish peroxidase.

show abstract

“…66 Horseradish peroxidase is inactivated by hydrazines such as phenylethyl and methylhydrazine via an isoporphyrin intermediate which eventually undergo δ-meso-alkylation of the prosthetic heme group. 67 There is a report on oxidation of nitropropane by horseradish peroxidase which rearranges to a modified enzyme, in which the nitromethyl group gets attached at the meso carbon atom. 68 Because of such types of modifications i.e., the formation of an isoporphyrin as an intermediate, the enzyme is inactivated during the reaction.…”

Section: Heme Oxidationmentioning

confidence: 99%

Metalloisoporphyrins: from synthesis to applications

Bhuyan

2015

Dalton Trans.

View full text Add to dashboard Cite

An overview of the chemistry of isoporphyrin, the tautomer of porphyrin, whose existence was predicated by the Noble laureate Woodward, is presented with emphasis on hydroxy-isoporphyrins of tetra-aryl derivatives. The chemistry of metalloisoporphyrin has been discussed since the discovery of the first metallo-isoporphyrin by Dolphin and co-workers, as no comprehensive article is available on this beautiful macrocycle. Attention is paid to the possible applications of metalloisoporphyrins as photosensitizers in photodynamic therapy, as a near infra-red dye and as a reactive agent for different atom transfer reactions. Some important findings about reactivity and theoretical results of hydroxy-isoporphyrins are discussed. Furthermore, the approaches of heme oxidation via isoporphyrin as an intermediate to understand the heme oxygenase mechanism are discussed. The metalloisoporphyrins are discussed reviewing coordination modes, structural changes, electronic properties and biological relevance.

show abstract

Stabilized Isoporphyrin Intermediates in the Inactivation of Horseradish Peroxidase by Alkylhydrazines

Cited by 44 publications

References 27 publications

The crystal structure of peanut peroxidase

The crystal structure of peanut peroxidase

Asymmetric Sulfoxidation of Thioether Catalyzed by Soybean Pod Shell Peroxidase to Form Enantiopure Sulfoxide in Water‐in‐Oil Microemulsions: A Kinetic Model

Metalloisoporphyrins: from synthesis to applications

Contact Info

Product

Resources

About