45th Annual Meeting of the European Society for Paediatric Endocrinology (ESPE) location:Rotterdam, The Netherlands date:30 June – 3 July 2006
Proteomics and peptidomics represent global strategies, where all proteins
or peptides present in a biological sample derived from a cell, tissue, body
liquid, or whole organism are simultaneously visualised and identified. Both
technologies target different windows of the proteome and therefore require
a specific methodology.
Two-dimensional polyacrylamide gel electrophoresis is the key technology
for proteomics. Here, proteins are separated according to their isoelectric
point and molecular weight, allowing the separation of several thousand
proteins in a single gel and downstream identification by mass spectrometry.
For an accurate quantitative comparison of different samples with statistical
confidence, 2D-DIGE (2D-difference gel electrophoresis) is the method of
choice. Here, multiple protein extracts are labelled with different fluorescent
dyes and subsequently separated on the same 2D gel. A reference sample is
used, known as an internal standard, which comprises equal amounts of all
biological samples in the experiment, controlling for non-biologic variation.
Biologically active peptides are important substances that transmit and regulate
bio-information in the circulatory and neuronal systems. This restricted
window of the proteome (< 10 kDa) is however not covered by conventional
gel electrophoresis and prompted the development of other extraction procedures
and separation tools. This new research field was termed peptidomics.
The most common tool used for peptidomics is a combination of nanoscale
liquid chromatography, tandem mass spectrometry and database mining,
which allows the detection and sequencing of low concentrations of peptides
from complex mixtures with a high degree of automation.
Both proteomics and peptidomics are important tools in the study of the
mechanism of diseases, the investigation for diagnostic biomarkers and pinpointing
of novel therapeutic targets.