A Novel Protease for Proteomics
Tech ID: 22224 / UC Case 2012-221-0
BackgroundAlthough every cell contains the entire genome of the organism, only some of the genes are transcribed and translated in a particular cell type. Cellular functions can, therefore, only be understood once each cellular proteome is known. One of the most important tools in identifying all of the proteins and their post-translational modifications in a particular cell involves digesting the entire mixture of proteins all at the same time, and then piecing the sequence information back together at the end. Nearly all proteomics studies are carried out with a single protease digestion step using trypsin. Sequence coverage of abundant proteins using currently available proteases may approach 50 percent but sequence coverage of most proteins is less than 10 percent. In order to increase the sequence coverage, proteases of alternative specificity are needed.
Technology DescriptionUC San Diego researchers have discovered a stable, highly active protease with aliphatic substrate specificity that can complement trypsin for quantitative proteomics. Alpha-lytic protease (aLP) is a bacterial protease with specificity to cleave primarily after T(threonine), V(valine), and S(serine) when applied to proteomics. The average peptide length is about the same as for trypsin digests with a high probability of containing unique sequences, and very little evidence of laddering. The combination of aLP and trypsin doubles the number of proteins coverage.
ApplicationsProteomic sequencing experiments for all proteins and their post-translational modifications.
AdvantagesDigestion of an S. Pombe proteome with aLP identifies over six hundred proteins with high confidence when CID is used for fragmentation. The combination of aLP and trypsin doubles the number of proteins showing significant iTRAQ quantifiable changes (p-value <0.05, Protein Pilot searched) when compared to trypsin alone.
protease, proteomics, alpha-lytic protease