If the dominant species is an oxidation product the finding is about handling; if it is a deletion or a diastereomer the finding is about synthesis. On this record it is D-carnosine epimer, which settles the question.
oxidation_ladder
Sequential methionine oxidation and reading the rungs.
Section 1
Contribution
Comments technically on records submitted by others. Annotations are signed and are not moderated for agreement.
Records submitted
0
n=0
Annotations
21
n=21
Median purity submitted
suppressed
n=0
n<3 — see individual records
Suppliers covered
0
n=0
This handle has submitted no records. Annotators comment on other people's submissions and are not required to submit.
Section 2
Annotations
Signed technical comments on records. The index does not moderate annotations for agreement with its own arithmetic, and several of these disagree with it. Where a handle has made the same point on several records, one instance is shown and the rest are reachable from the records themselves.
If the dominant species is an oxidation product the finding is about handling; if it is a deletion or a diastereomer the finding is about synthesis. On this record it is Met(O) sulfoxide (+16 Da), which settles the question.
If the species is a tryptophan oxidation product rather than a methionine one, container choice matters more than temperature. Clear glass on a Trp-containing sequence is a light-exposure problem.
If the dominant species is an oxidation product the finding is about handling; if it is a deletion or a diastereomer the finding is about synthesis. On this record it is [D-Thr]-diastereomer, which settles the question.
If the dominant species is an oxidation product the finding is about handling; if it is a deletion or a diastereomer the finding is about synthesis. On this record it is des-Met (−131 Da), which settles the question.
Trace metal in the vial catalyses oxidation. A chelator in the formulation suppresses it, and research-grade lyophilisates are formulated with nothing at all.
If the dominant species is an oxidation product the finding is about handling; if it is a deletion or a diastereomer the finding is about synthesis. On this record it is glutathione disulfide (GSSG, +305 Da), which settles the question.
Photo-oxidation and thermal oxidation produce overlapping but distinguishable product distributions. Where both a Met and a Trp product are present, light is implicated more strongly than temperature.
If the dominant species is an oxidation product the finding is about handling; if it is a deletion or a diastereomer the finding is about synthesis. On this record it is Pro-Val dipeptide (−128 Da), which settles the question.
The rungs are readable: sulfoxide, then sulfone, then backbone fragments. How far up the ladder a lot has climbed dates its exposure better than any single figure.
If the dominant species is an oxidation product the finding is about handling; if it is a deletion or a diastereomer the finding is about synthesis. On this record it is des-Gln truncate (−128 Da), which settles the question.
If the dominant species is an oxidation product the finding is about handling; if it is a deletion or a diastereomer the finding is about synthesis. On this record it is des-Lys (−128 Da), which settles the question.
Showing 12 distinct comments of 21 annotations by this handle.