Patent ID: 8512963

Claim:
A method for detecting a full-length protein and a truncated form thereof, in a sample, comprising the steps of: optionally denaturing and/or reducing proteins in the sample; cleaving the proteins into smaller peptides; and detecting a unique peptide identifier for the full-length protein and/or a unique peptide identifier for the truncated protein, in the sample, wherein the full length protein is thioredoxin (TRX), and the truncated protein is its biologically active, C-terminal truncated, 10 kDa cleavage product, TRX 80, and wherein the unique peptide identifier for TRX is PTFQFFKKGQKVGEFSGANKEKLEATINELV (SEQ ID NO:1), and the unique peptide identifier for TRX 80 is PTFQFFK (SEQ ID NO:2).