Isoelectric point based signal suppression in MALDI-TOF MS to identify cancer biomarkers including HMGB1 from human tissue and serum

摘要

Human serum and tissues are complex mixtures of proteins in differing amounts making identification of lower abundance proteins challenging. HMGB1 is a member of the HMGB family and an important mediator in stressed tissues. Its over-expression signifies poor prognoses in many tumor types. HMGB1 is a basic protein that has an acidic tail. Its different tryptic fragments have a wide range of isoelectric points (pI). We have used this protein as a model system for identifying biomarkers from human serum and diseased and healthy liver and pancreas based on the pI of its tryptic peptides. Selectively suppressing the signal of irrelevant peptides based on their pI will improve detection of biomarkers with different pI's.