Oxyhalogen–sulfur chemistry — Kinetics and mechanism of oxidation of methionine by aqueous iodine and acidified iodate

2009 ◽  
Vol 87 (6) ◽  
pp. 689-697 ◽  
Author(s):  
Edward Chikwana ◽  
Bradley Davis ◽  
Moshood K. Morakinyo ◽  
Reuben H. Simoyi
Keyword(s):  
Methionine Sulfoxide ◽  
Molecular Iodine ◽  
Reaction Scheme ◽  
Direct Reaction ◽  
Sulfur Chemistry ◽  
Reaction Characteristics ◽  
Mechanism Of Oxidation ◽  
Oxidation Of Methionine ◽  
Simple Network ◽  
Clock Reaction

The oxidation of methionine (Met) by acidic iodate and aqueous iodine was studied. Though the reaction is a simple two-electron oxidation to give methionine sulfoxide (Met–S=O), the dynamics of the reaction are, however, very complex, characterized by clock reaction characteristics and transient formation of iodine. In excess methionine conditions, the stoichiometry of the reaction was deduced to be IO3– + 3Met → I– + 3Met–S=O. In excess iodate, the iodide product reacts with iodate to give a final product of molecular iodine and a 2:5 stoichiometry: 2IO3– + 5Met + 2H+ → I2 + 5Met–S=O + H2O. The direct reaction of iodine and methionine is slow and mildly autoinhibitory, which explains the transient formation of iodine, even in conditions of excess methionine in which iodine is not a final product. The whole reaction scheme could be simulated by a simple network of 11 reactions.

Oxyhalogen–Sulfur Chemistry: Kinetics and Mechanism of Oxidation of N-Acetyl-ʟ-methionine by Aqueous Iodine and Acidified Iodate

2014 ◽  
Vol 67 (4) ◽  
pp. 626 ◽  
Author(s):  
Kudzanai Chipiso ◽  
Wilbes Mbiya ◽  
Moshood K. Morakinyo ◽  
Reuben H. Simoyi
Keyword(s):  
Methionine Sulfoxide ◽  
Kinetics And Mechanism ◽  
Ionization Mass ◽  
Stoichiometric Ratio ◽  
Inhibitory Effects ◽  
Electron Transfer Process ◽  
Sulfur Chemistry ◽  
Methionine Supplementation ◽  
Mechanism Of Oxidation ◽  
Sole Product

The use of N-acetyl-l-methionine (NAM) as a bio-available source for methionine supplementation as well as its ability to reduce the toxicity of acetaminophen poisoning has been reported. Its interaction with the complex physiological matrix, however, has not been thoroughly investigated. This manuscript reports on the kinetics and mechanism of oxidation of NAM by acidic iodate and aqueous iodine. Oxidation of NAM proceeds by a two electron transfer process resulting in formation of a sole product: N-acetyl-l-methionine sulfoxide (NAMS=O). Data from electrospray ionization mass spectrometry confirmed the product of oxidation as NAMS=O. The stoichiometry of the reaction was deduced to be IO3– + 3NAM → I– + 3NAMS=O. In excess iodate, the stoichiometry was deduced to be 2IO3– + 5NAM + 2H+ → I2 + 5NAMS=O + H2O. The reaction between aqueous iodine and NAM gave a 1 : 1 stoichiometric ratio: NAM + I2 + H2O → NAMS=O + 2I– + H+. This reaction was relatively rapid when compared with that between NAM and iodate. It did, however, exhibit some auto-inhibitory effects through the formation of triiodide (I3–) which is a relatively inert electrophile when compared with aqueous iodine. A simple mechanism containing 11 reactions gave a reasonably good fit to the experimental data.

scholarly journals Peptide-Bound Methionine Sulfoxide (MetO) Levels and MsrB2 Abundance Are Differentially Regulated during the Desiccation Phase in Contrasted Acer Seeds

Antioxidants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 391 ◽  
Author(s):  
Natalia Wojciechowska ◽  
Shirin Alipour ◽  
Ewelina Stolarska ◽  
Karolina Bilska ◽  
Pascal Rey ◽  
...  
Keyword(s):  
Desiccation Tolerance ◽  
Methionine Sulfoxide ◽  
Redox Status ◽  
Embryonic Axes ◽  
Seed Desiccation ◽  
Methionine Sulfoxide Reductases ◽  
Norway Maple ◽  
Orthodox Seeds ◽  
Oxidation Of Methionine ◽  
Reduced Forms

Norway maple and sycamore produce desiccation-tolerant (orthodox) and desiccation-sensitive (recalcitrant) seeds, respectively. Drying affects reduction and oxidation (redox) status in seeds. Oxidation of methionine to methionine sulfoxide (MetO) and reduction via methionine sulfoxide reductases (Msrs) have never been investigated in relation to seed desiccation tolerance. MetO levels and the abundance of Msrs were investigated in relation to levels of reactive oxygen species (ROS) such as hydrogen peroxide, superoxide anion radical and hydroxyl radical (•OH), and the levels of ascorbate and glutathione redox couples in gradually dried seeds. Peptide-bound MetO levels were positively correlated with ROS concentrations in the orthodox seeds. In particular, •OH affected MetO levels as well as the abundance of MsrB2 solely in the embryonic axes of Norway maple seeds. In this species, MsrB2 was present in oxidized and reduced forms, and the latter was favored by reduced glutathione and ascorbic acid. In contrast, sycamore seeds accumulated higher ROS levels. Additionally, MsrB2 was oxidized in sycamore throughout dehydration. In this context, the three elements •OH level, MetO content and MsrB2 abundance, linked together uniquely to Norway maple seeds, might be considered important players of the redox network associated with desiccation tolerance.

Oxyhalogen–Sulfur Chemistry: Kinetics and Mechanism of Oxidation of 1,3-Dimethylthiourea by Acidic Bromate

2017 ◽  
Vol 121 (34) ◽  
pp. 6366-6376 ◽  
Author(s):  
Olufunke Olagunju ◽  
Reuben H. Simoyi
Keyword(s):  
Kinetics And Mechanism ◽  
Sulfur Chemistry ◽  
Mechanism Of Oxidation

Oxyhalogen–Sulfur Chemistry: Kinetics and Mechanism of Oxidation of Captopril by Acidified Bromate and Aqueous Bromine

2013 ◽  
Vol 117 (13) ◽  
pp. 2704-2717 ◽  
Author(s):  
G. P. Kapungu ◽  
G. Rukweza ◽  
Thai Tran ◽  
Wilbes Mbiya ◽  
Risikat Adigun ◽  
...  
Keyword(s):  
Kinetics And Mechanism ◽  
Sulfur Chemistry ◽  
Mechanism Of Oxidation

The Quantitative Oxidation of Methionine to Methionine Sulfoxide by Peroxynitrite

2000 ◽  
Vol 377 (2) ◽  
pp. 266-272 ◽  
Author(s):  
Daniel Perrin ◽  
Willem H. Koppenol
Keyword(s):  
Methionine Sulfoxide ◽  
Oxidation Of Methionine

Oxyhalogen−Sulfur Chemistry:  Kinetics and Mechanism of Oxidation of Guanylthiourea by Acidified Bromate1

2004 ◽  
Vol 108 (52) ◽  
pp. 11591-11599 ◽  
Author(s):  
Edward Chikwana ◽  
Adenike Otoikhian ◽  
Reuben H. Simoyi
Keyword(s):  
Kinetics And Mechanism ◽  
Sulfur Chemistry ◽  
Mechanism Of Oxidation

Iron-thiolate induced oxidation of methionine to methionine sulfoxide in small model peptides. Intramolecular catalysis by histidine

1993 ◽  
Vol 1158 (3) ◽  
pp. 307-322 ◽  
Author(s):  
Christian Schöneich ◽  
Fang Zhao ◽  
George S. Wilson ◽  
Ronald T. Borchardt
Keyword(s):  
Methionine Sulfoxide ◽  
Intramolecular Catalysis ◽  
Iron Thiolate ◽  
Small Model ◽  
Oxidation Of Methionine ◽  
Model Peptides

scholarly journals Oxidation of Methionine 77 in Calmodulin Alters Mouse Development and Behavior

2018 ◽  
Author(s):  
Méry Marimoutou ◽  
Danielle A. Springer ◽  
Chengyu Liu ◽  
Geumsoo Kim ◽  
Rodney Levine
Keyword(s):  
Open Field ◽  
Stress Test ◽  
Young Male ◽  
Methionine Sulfoxide ◽  
Methionine Sulfoxide Reductase ◽  
Mutant Mice ◽  
Wild Type ◽  
Mouse Development ◽  
Oxidation Of Methionine

Methionine 77 in calmodulin can be stereospecifically oxidized to methionine sulfoxide by mammalian methionine sulfoxide reductase A. Whether this has in vivo significance is unknown. We therefore created a mutant mouse in which wild-type calmodulin-1 was replaced by a calmodulin containing a mimic of methionine sulfoxide at residue 77. Total calmodulin levels were unchanged in the homozygous M77Q mutant, which is viable and fertile. No differences were observed on learning tests, including the Morris water maze and associative learning. Cardiac stress test results were also the same for mutant and wild type mice. .However, young male and female mice were 20% smaller than wild type mice, although food intake was normal for their weight. Young M77Q mice were notably more active and exploratory than wild type mice. This behavior difference was objectively documented on the treadmill and open field tests. The mutant mice ran 20% longer on the treadmill than controls, and in the open field test, the mutant mice explored more than controls and exhibited reduced anxiety These phenotypic differences bore a similarity to those observed in mice lacking calcium/calmodulin kinase Iiα (CaMKIIα). We then showed that M77Q calmodulin was less effective in activating CaMKIIα than wild type calmodulin. Thus, characterization of the phenotype of a mouse expressing a constitutively active mimic of calmodulin led to the identification of the first calmodulin target that can be differentially regulated by the oxidation state of Met77. We conclude that reversible oxidation of methionine 77 in calmodulin by MSRA can regulate cellular function.

Oxyhalogen−Sulfur Chemistry:  Kinetics and Mechanism of Oxidation ofN-Acetylthiourea by Chlorite and Chlorine Dioxide1

2006 ◽  
Vol 110 (7) ◽  
pp. 2396-2410 ◽  
Author(s):  
Olufunke Olagunju ◽  
Paul D. Siegel ◽  
Rotimi Olojo ◽  
Reuben H. Simoyi
Keyword(s):  
Kinetics And Mechanism ◽  
Sulfur Chemistry ◽  
Mechanism Of Oxidation

scholarly journals Oxidation of Methionine 77 in Calmodulin Alters Mouse Growth and Behavior

Antioxidants ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 140 ◽  
Author(s):  
Méry Marimoutou ◽  
Danielle Springer ◽  
Chengyu Liu ◽  
Geumsoo Kim ◽  
Rodney Levine
Keyword(s):  
Open Field ◽  
Stress Test ◽  
Field Tests ◽  
Young Male ◽  
Methionine Sulfoxide ◽  
Methionine Sulfoxide Reductase ◽  
Mutant Mice ◽  
Wild Type ◽  
Oxidation Of Methionine

Methionine 77 in calmodulin can be stereospecifically oxidized to methionine sulfoxide by mammalian methionine sulfoxide reductase A. Whether this has in vivo significance is unknown. We therefore created a mutant mouse in which wild type calmodulin-1 was replaced by a calmodulin containing a mimic of methionine sulfoxide at residue 77. Total calmodulin levels were unchanged in the homozygous M77Q mutant, which is viable and fertile. No differences were observed on learning tests, including the Morris water maze and associative learning. Cardiac stress test results were also the same for mutant and wild type mice. However, young male and female mice were 20% smaller than wild type mice, although food intake was normal for their weight. Young M77Q mice were notably more active and exploratory than wild type mice. This behavior difference was objectively documented on the treadmill and open field tests. The mutant mice ran 20% longer on the treadmill than controls and in the open field test, the mutant mice explored more than controls and exhibited reduced anxiety. These phenotypic differences bore a similarity to those observed in mice lacking calcium/calmodulin kinase IIα (CaMKIIα). We then showed that MetO77 calmodulin was less effective in activating CaMKIIα than wild type calmodulin. Thus, characterization of the phenotype of a mouse expressing a constitutively active mimic of calmodulin led to the identification of the first calmodulin target that can be differentially regulated by the oxidation state of Met77. We conclude that reversible oxidation of methionine 77 in calmodulin by MSRA has the potential to regulate cellular function.

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