California Institute of Technology

Thermo Fisher Scientific (bremen) Gmbh

Michael Sweredoski

Jens Griep-Raming

John M Eiler

Sonja Hess

Tanya R Yakushi

Roxana Eggleston-Rangel

Annie Moradian

Simon Cajetan Neubauer

A method for determining an isotopic profile for a molecule is provided. The isotopic profile is indicative of an isotopic content for the molecule. The method comprises mass selecting ions of the molecule in a mass window, the mass window excluding a mass for a monoisotopic molecular ion and including a mass for at least one isotopic variant of the monoisotopic molecular ion. The method comprises fragmenting the mass selected ions into fragment ions, performing mass analysis on one or more of the fragment ions to produce a mass spectrum, and determining the isotopic profile for the molecule, the isotopic profile comprising at least one data value. Each data value is calculated for a fragment ion as a function of intensities of multiple peaks in the mass spectrum. A computer program is provided. A mass spectrometry system is provided. A method for identifying a sample is provided.

Isotopic mass spectrometer

A method for preparing a methionine containing peptide or protein for analysis by mass spectrometry by incubating the methionine containing peptide or protein with a heterologous methionine sulfoxide reductase A (MsrA), a heterologous methionine sulfoxide reductase B (MsrB), or a heterologous methionine sulfoxide reductase AB (MsrAB) enzyme results in the reduction of an oxidized methionine containing peptide or protein.

Reduction of oxidated methionine peptides for mass spectrometry

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Altadena, CA, United States of America

Michael Sweredoski