Sperm Proteomics: Road to Male Fertility and Contraception

Figure 2

Schematic diagram showing the extraction and analysis of proteins from sperm cells. After collection and liquefaction of a whole semen sample, it can be used as it is or it can be subjected to density gradient centrifugation to separate mature and immature sperm populations. The recovered spermatozoa can be extracted and purified, after which the protein concentration can be determined in order to allow for an equal protein-loading gradient on electrophoretic gels. The further analysis of the sperm proteome is done from an aliquot of the sperm cells by using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) followed by excision of protein spots from the 2D-PAGE gels and matrix-assisted laser desorption/ionization-mass spectroscopy (MALDI-MS) or tandem MS (MS/MS) identification. Alternatively, the initial protein extract can be digested into peptides, which can be separated via liquid chromatography, followed by MS/MS analysis.