Proteomics Using Proteases Alternative to Trypsin Benefits from Sequential Digestion with Trypsin

ABSTRACT: High specificity and ease of use make trypsin the most used enzyme in proteomics. Proteases with complementary cleavage specificity to trypsin have been applied to obtain additional data. However, use of proteases with broad specificity proved especially challenging. In this work, we analyzed the characteristics of five protease alternatives to trypsin for protein identification and sequence coverage when applied to S. pombe whole cell lysates. The specificity of the protease heavily impacted on the number of proteins identified. Proteases with higher specificity let to the identification of more proteins than proteases with lower specificity. However, AspN, GluC, chymotrypsin and proteinase K largely benefited from being paired with trypsin in sequential digestion, as had been shown by us for elastase before. In the most extreme case, the addition of trypsin to a proteinase K digest increased the number of identified proteins by 524 %. Also, AspN (82 %) and GluC (74 %) protein identifications largely improved following the additional digestion with trypsin. In general, protein identifications improved most over the use of the single protease when the enzymes followed on an initial digestion with trypsin. In the most extreme case, the sequential digest with trypsin and AspN yielded even higher number of protein identifications than digesting with trypsin alone.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Schizosaccharomyces Pombe Oy26

SUBMITTER: Therese Dau  

LAB HEAD: Juri Rappsilber

PROVIDER: PXD017321 | Pride | 2021-06-07

REPOSITORIES: Pride