In pig, phosphorylation drives binding specificity of recombinant OBP (stricto sensu, referred as OBP in this text) isoforms (Brimau et al., 2010) that are not O-GlcNAcylated, contrary to native OBP, purified from nasal tissue (Nagnan-Le Meillour et al., 2014). In order to precise the role of both PTM in OBP binding abilities to pheromone components in pig, we purified OBP isoforms by HPLC and performed structure-function relationship study. We have identified phosphorylation and O-GlcNAcylation on 4 OBP isoforms by immunodetection with specific antibodies, with careful controls. The binding properties of the 4 isoforms were monitored by fluorescence spectroscopy in exactly the same conditions previously used for recombinant OBP isoforms (Brimau et al., 2010). The PTM sites were mapped by CID-nano-LC-MS/MS and BEMAD (for phosphorylation) to link the binding affinities to phosphorylation and O-GlcNAcylation patterns of native OBP isoforms. Comparison of binding affinities between recombinant (only phosphorylated) and native (also O-GlcNAcylated) isoforms indicates that O-GlcNAcylation increases the binding specificity to pheromone components. This is the first time that such PTM sites are localized in OBP by high-resolution mass spectrometry, and that a demonstration of their involvement in odorant molecules discrimination by OBP isoforms is given