BIOL 3095 September 30, 2011. Reflection on Seminar 2: “Proteomic biomarker discovery.” By: Angélica M. González Sánchez Student number: 804-11-3354 On the seminar given by the Ph.D. candidate, Ms. Lisandra Santiago, she discussed proteomics, thetopic of her research. This is the study of protein’s structure and function and it is particularly important in thediscovery of biomarkers for diseases. That’s why new techniques are being implemented to improve its job,such as the characterization of phosphorylated peptides using mass spectrometry, which is shown to be the mostcommon, sensitive and effective one. However, mass spectrometry can’t be efficient enough on its own. That’swhy it is usually used as a part of shotgun proteomics. This is a process of obtaining, processing and identifyingproteins. It mainly consists of taking out proteins from samples (plasma or tissue), digesting the proteins intopeptides, fractionating them by liquid chromatography, processing them through mass spectrometry, comparingthe resulting proteins on data bases and determining the potential biomarkers for the disease. The problem withthis approach is that it identifies too many proteins, making the validation process longer and the specificity of thebiomarkers uncertain. That’s why some pioneering approaches for biomarker discovery have developed, such asthe combination of tissue and plasma samples and new experimental designs to detect the bioactivity of proteins.However, we learned that the field of proteomics still needs to “evaluate the entire process right from sampleacquisition to bioinformatics analysis with the aim to implement and develop innovative strategies” (Veenstra,2011). From my perspective, this seminar was very enriching because it showed new concepts which are veryremarkable and relevant for actual investigations. It resulted quite valuable because it communicated severalresearch techniques that are currently used in the Science field.