UniMod

UniMod catalogs protein modifications and their precise mass differences to support mass spectrometry–based proteomics applications such as protein identification and de novo sequencing.

Key Features:

• Modification repository: Catalogs protein modifications with recorded elemental compositions.
• Mass-difference values: Provides accurate, verifiable mass-difference values for each listed modification.
• Natural and artificial modifications: Includes both naturally occurring post-translational modifications and artificially induced modifications.
• Spectral matching support: Enables matching of observed mass shifts in experimental spectra to known modifications.
• De novo sequencing support: Facilitates de novo sequencing by relating theoretical mass changes from modifications to empirical data for sequence and site inference.

Scientific Applications:

• Protein identification: Supports identification of proteins in mass spectrometry proteomics by providing modification mass offsets.
• De novo sequencing: Assists sequencing efforts without prior sequence knowledge by enabling interpretation of modification-induced mass shifts.
• Spectrum interpretation: Improves interpretation of complex mass spectra by supplying modification-specific mass and composition data.
• Post-translational modification characterization: Aids in detection and localization of post-translational modifications based on mass changes.

Methodology:

Catalogs modifications by elemental composition and precise mass differences, provides mass-difference values, matches observed mass shifts in experimental spectra to known modifications, and compares theoretical mass changes due to modifications with empirical spectra to infer sequences and modification sites.