Abstract: Chemoproteomic methods for detecting and profiling electrophilic post-translational modifications (PTMs) and oxidative PTMs in proteins are described. The methods including contacting a proteomic mixture with a probe having hydrazine and alkyne moieties or oxyamine and alkyne moieties to form a covalent linkage between the hydrazine or oxyamine moiety of the probe and the electrophilic PTM or oxidative PTM of the protein. The resulting alkyne-derivatized proteins are labelled with an azide modified tag via a click chemistry reaction. The labelled proteins can then be detected or profiled using techniques such as, for example, fluorescence imaging or mass spectrometry. Also described are protein conjugates having a covalent linkage formed by reaction of a hydrazine or oxyamine moiety of a probe with an electrophilic or oxidative PTM of a protein.