Digging More Missing Proteins Using an Enrichment Approach with ProteoMiner

Human
Proteome Project (HPP) aims at mapping entire human proteins
with a systematic effort upon all the emerging techniques, which would
enhance understanding of human biology and lay a foundation for development
of medical applications. Until now, 2563 missing proteins (MPs, PE2–4)
are still undetected even using the most sensitive approach of protein
detection. Herein, we propose that enrichment of low-abundance proteins
benefits MPs finding. ProteoMiner is an equalizing technique by reducing
high-abundance proteins and enriching low-abundance proteins in biological
liquids. With triton X-100/TBS buffer extraction, ProteoMiner enrichment,
and peptide fractionation, 20 MPs (at least two non-nested unique
peptides with more than eight a.a. length) with 60 unique peptides
were identified from four human tissues including eight membrane/secreted
proteins and five nucleus proteins. Then 15 of them were confirmed
with two non-nested unique peptides (≥9 a.a.) identified
by matching well with their chemically synthetic peptides in PRM assay.
Hence, these results demonstrated ProteoMiner as a powerful means
in discovery of MPs.