Fig. 2.

Schematic representation of the strategy used to identify and quantify sialylated N-linked glycopeptides extracted from mouse sperm. Sperm cells retrieved from mouse epididymides were divided into two groups: one incubated in capacitating conditions (supplemented with 1 mm pentoxifylline and 1 mm dibutyryl-cAMP) and the other in noncapacitating conditions (without supplementation and sodium bicarbonate). Sperm proteins were recovered and digested (trypsin). Sialylated-glycoproteins were enrichment using TiO₂ beads. The N-linked glycopeptides were eluted from the beads after PNGase F treatment and then identified and quantified using LC–MS/MS and label-free techniques. “-D” represents deamidates asparagine.