Accordingly, systems and methods for protein identification are provided. The present teaching provide for a system with one protein identification methodology based on one method and a second protein identification methodology based on a second protein identification methodology to interact and increase confidence in protein identification. Various embodiments employ protein identification methodologies that identify portions of a peptide. Various embodiments provide for a hypothesis generation module that can suggest modifications for the peptide based on differences between experimental and theoretical values. Various embodiments provide for an identifier module that can select one or more hypotheses from the hypothesis module as most probable. In this way, the present teachings can provide for systems and methods to combine protein identification results from multiple protein identification methodologies with the possibility of identifying modifications.