Mass spectrometric profiling of low-molecular-weight proteins

Tracing potential biomarkers through proteomics has been further developed and is nearing realization. The whole sequence of human proteome is becoming better understood with the passage of time. However, it is a long way to go to pinpoint biomarker proteins out of complex biofluids and use them for clinical diagnosis, prognosis, and therapeutic applications. From that point of view, the high hopes put in proteomics have not been fulfilled yet. The key reasons for that is the complexity of the proteome and the limited technologies in terms of specificity and reproducibility. Thus, major focus is put on the development of novel innovative analytical techniques in the field of life science, using high-performance single- and multidimensional separation and enrichment methods, such as solid-phase extraction (SPE), liquid chromatography (HPLC), or capillary electrophoresis (CE) coupled to mass spectrometry (MS). A newly emerged technology, termed as material-enhanced laser desorption/ionization (MELDI) meets basic requirements and is applied to reduce the complexity of proteomic samples while liquid chromatography (LC) is used for separation and fractionation, followed by identification with MS/MS including database searching analysis. Different MELDI carriers are employed as support materials to specifically bind peptides and proteins from biofluids like serum or urine. The MELDI approach supports automated routine analysis by means of liquid handling robots for high-throughput applications leading to higher reproducibility, crucial for a successful identification of disease markers with MALDI-TOF MS. Such promising new methods and further technical developments will be necessary to answer the high-wrought expectations on the field of proteomics.