The rapid development of mass spectrometry now allows the investigation of very complex proteins mixtures from subcellular structures to tissues. Body fluids are also popular targets of proteomic analysis due their potential for biomarker discovery. Seminal plasma has not yet received much attention from the proteomics community but its characterization could provide a future reference for virtually all studies involving human sperm. The fluid is essential for spermatozoa survival and their successful journey through the female reproductive tract.
	Here we report highly confident identification of 892 proteins in seminal fluid from a single individual. Fourier Transform mass spectrometry enabled parts per million mass accuracy and two consecutive stages of mass spectrometric fragmentation allowed confident identification of proteins even by single peptides. GoMiner analysis annotated two thirds of the seminal fluid proteome and revealed a large number of extracellular proteins including many proteases. Other proteins originated from male accessory glands and play important role in spermatozoa survival.
	This high confidence characterization of seminal plasma content provides an inventory of proteins with potential roles in fertilization. When combined with quantitative proteomics methodologies, it should be useful for studies of fertilization, male infertility and prostatic and testicular cancers.
	This database accompanies the article: Pilch B, Mann M., Large-scale and high confidence proteomic analysis of human seminal plasma, Genome Biol. 2006;7(5):R40. Epub May 18 (2006)