Using the Ladder Sequencing Toolbox

7.Under Annotate Spectrum, select the types of labels you want displayed:

Reference Mass (*)Mass of the reference peak against which the current peak is compared.

Mass DifferenceDifference between the current peak and the reference, preceded by a minus sign (–).

Peak MassMass of the current peak, preceded by an equal sign (=).

8.Click Label Peaks.

If Peptide is selected, the software:

Examines the spectrum in 55 Da increments

and selects the most intense ion in the range.

(The 55 Da increment is used because it is C less than the smallest mass difference related

to a residue.)

Labels mass differences (plus or minus the specified Tolerance) that correspond to amino acids.

Labels the reference peak from which the mass difference was derived with an asterisk (*).

Applies the additional labels you selected under Annotate Spectrum.

Data ExplorerSoftware User’s Guide

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