3226-65-1Relevant articles and documents
Structural studies on the stereoisomerism of a natural dye miraxanthin I
Niziński, Stanis?aw,Popenda, ?ukasz,Rode, Micha? F.,Kumorkiewicz, Agnieszka,Fojud, Zbigniew,Paluch-Lubawa, Ewelina,Wybraniec, S?awomir,Burdziński, Gotard
, p. 18165 - 18174 (2019)
The chemical structure of a yellow dye present in Mirabilis jalapa L., miraxanthin I, was characterized by NMR spectroscopy. The extract of M. jalapa was analysed by a high-performance liquid chromatographic system (LC-DAD-FL-ESI-MS/MS) and the presence of miraxanthin I among other betaxanthins was confirmed. This dye was synthesized from previously generated methionine-betaxanthin by oxidation with 10% H2O2. The E/Z stereoisomers of miraxanthin I were found by NMR analysis to occur in a 50?:?33?:?10?:?7 ratio in aqueous solution (7E,9E?:?7Z,9E?:?7E,9Z?:?7Z,9Z configurations, respectively). Comparison of NMR data with chemical shifts obtained from quantum chemical calculations strongly suggests the presence of intramolecular hydrogen bonds which may favour a more rigid structure of the dye. This explains the highest fluorescence quantum yield among betaxanthins. The observed changes in the 1H NMR spectra during the measurements indicate on miraxanthin I hydrolysis for which a mechanism is proposed. The first step during the hydrolysis process is protonation of the nitrogen atom within the central bridge bond system which is observed in the ZE stereoisomer by NMR.
Diastereomers of Methionine S-Oxide in the Hinge-Ligament Proteins of Molluscan Bivalve Species
Kikuchi, Yasuo,Higashi, Kiyoshi,Tamiya, Nobuo
, p. 2083 - 2088 (1988)
The diastereomer ratio was analyzed on methionine S-oxide residues formed by in vivo posttranslational oxidation of methionine residues in a protein.The hinge-ligament protein of molluscan bivalves is distinct from usual proteins in containing a large amount of methionine S-oxide.The methionine S-oxide was released from the protein by proteolytic digestions and was found to be a mixture of approximately equall amounts of two diastereomers, (5S)- and (5R)-L-methionine S-oxide.
Kinetics and mechanism of the oxidation of DL-methionine by tetrakis(pyridine)silver dichromate
Patel,Mathur,Jha,Kothari,Shastri,Sharma, Pradeep K.
, p. 2779 - 2782 (2013)
The oxidation of methionine by tetrakis(pyridine)silver dichromate in dimethyl sulphoxide leads to the formation of corresponding sulphoxide. The reaction is of first order with respect to tetrakis(pyridine)silver dichromate. Michaelis-Menten type kinetic
Periodate influencing diperiodatocuprate(III) oxidation of sulfur containing amino acid in aqueous alkaline medium
Sharanabasamma,Salunke, Manjali S.,Tuwar, Suresh M.
, p. 1217 - 1225 (2008)
The diperiodatocuprate(III) (DPC) oxidation of DL-methionine, a sulfur containing amino acid, was studied spectrophotometrically in alkaline solution. The reaction rate was first order in the concentration of DPC and fractional order in the concentration
Characterization by mass spectrometry and IRMPD spectroscopy of the sulfoxide group in oxidized methionine and related compounds
Ignasiak, Marta,Scuderi, Debora,De Oliveira, Pedro,Pedzinski, Tomasz,Rayah, Yamina,Houée Levin, Chantal
, p. 29 - 36 (2011)
Methionine protein residues are prone to oxidation. To unravel the controversy about the mechanism of its one-electron oxidation, we characterised the main biological product, methionine sulfoxide, using mass spectrometry and IR multiple photon dissociation spectroscopy. Gas phase IR spectra in the 800-2000 cm-1 range of protonated methionine and its sulfoxide were recorded and compared to those computed for the lowest energy structures. The signature of the SO bond was clearly identified at around 1000 cm-1. Oxidation of methionine-lysine dipeptide by OH radicals in the presence of catalase revealed the formation of methionine sulfoxide upon one-electron oxidation.
Electron transfer reactions of methionine peptides with photochemically generated ruthenium(III)-polypyridyl complexes
Thiruppathi, Dharmaraj,Karuppasamy, Periyakaruppan,Ganesan, Muniyandi,Sivasubramanian, Veluchamy Kamaraj,Rajendran, Thangamuthu,Rajagopal, Seenivasan
, p. 70 - 78 (2014)
The dynamics of the oxidation of five methionine carrying peptides with six Ru(III)-polypyridyl complexes in aqueous acetonitrile medium have been followed by spectrophotometric technique. The electron transfer (ET) reaction of [Ru(NN)3]3+
Accelerated Oxidation of Organic Sulfides by Microdroplet Chemistry
Li, Jia,Liu, Chengyuan,Chen, Hao,Zare, Richard N.
, p. 5011 - 5015 (2021/04/02)
We report the rapid oxidation of organic sulfides to sulfoxides by means of microdroplet chemistry at room temperature using a spray solution containing an organic sulfide dissolved in water/methanol, dilute (11%-14%) sodium hypochlorite (NaClO), and 5% chloroauric acid (HAuCl4). Ultrasonic nebulization, easy ambient sonic-spray ionization, or electrosonic spray ionization serves as the microdroplet source. High-resolution mass spectrometry was used as an online detector, and nuclear magnetic resonance was used as an offline detector. We found that the sulfoxide yields vary between 66 and 95%, the highest rate of product formation is 195 mg/min for benzyl phenyl sulfoxide, and the time required is a few minutes, which is much less than that required for the conventional means of achieving this chemical transformation. We also applied this microdroplet method to protein fingerprinting. We found that protein sequences containing methionine can be quickly oxidized, providing useful information for protein structure determinations.
