Introduction

Proteomics is made possible by the high-throughput detection, identification, and characterization of proteins in complex mixtures. High throughput refers to both the ability to detect many proteins per sample and to analyze many samples. While no method presently allows the rapid identification and quantification of all proteins in a mixture, intense research over the past decade has considerably accelerated the pace of protein measurements. Such measurements open the door to many applications in clinical and basic research.

Proteomics measurements rely on a combination of chemical separations, such as chromatography or electro-phoresis and mass spectrometry (MS). For top-down proteomics, the proteins themselves are separated and then analyzed, whereas for bottom-up proteomics the proteins are first digested with enzymes; the resulting peptides are then separated and analyzed by MS. Peptides detected are used to identify proteins by bioinformatics. The classical proteomic analysis tool is two-dimensional gel electrophoresis (2-D GE). This technique is powerful, allowing as many as 10,000 proteins to be detected in a single analysis. Spots detected on gels can be identified by extraction from the gel followed by enzyme digestion and MS analysis. 2-D GE is hindered by two disadvantages:

1) it requires relatively large samples (10" ~13to 10" 12mol);

2) it is slow and laborious, often requiring days for separation and much longer to extract and perform MS analysis of the spots.

Novel, automatable techniques that are faster and utilize miniscule samples are presently being developed to replace 2-D GE. One technique under investigation is microscale separation, such as capillary liquid chroma-tography (cLC) or capillary electrophoresis (CE), coupled with matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). In this approach, protein or peptide samples are resolved by cLC or CE and the fractions stored on the surface of a plate that is inserted into the mass spectrometer. Samples are examined by MALDI-MS to determine molecular weights and ultimately identify the protein or peptide. The method has been demonstrated to be able to detect as little as 10"18 to 10"15 mol of analyte in an automated, parallel format for high-throughput analysis. This potentially important proteomic technique is not presently commercially available, but is rapidly being developed. This article will discuss the state-of-the-art in coupling CE and cLC to MALDI-MS.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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