Agilent Technologies introduces lysine-tagging reagent kit for fast, accurate identification of rare proteins

Kit provides major improvement in popular approach to peptide sequencing for drug discovery, disease research

PALO ALTO, Calif., June 23, 2004

Agilent Technologies Inc. (NYSE: A) today introduced a chemical reagent kit that dramatically improves the sensitivity, speed and accuracy of peptide sequencing by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS), a popular analytical technique in protein research. The Agilent Lys Tag 4H reagent kit helps biologists to quickly and accurately detect and identify rare proteins, which could act as drug targets or biological markers in the detection of disease.

Researchers commonly identify rare proteins by breaking up (digesting) proteins with chemicals or enzymes and analyzing the resulting fragments (peptides) with MALDI-MS. The MS data is then matched against a database of known peptide digests to identify the parent protein. A major limitation of this approach is that it exhibits much greater (up to 18 times) sensitivity for arginine-containing peptides than for lysine-containing peptides. This limitation reduces the accuracy and coverage of protein identification since lysine-containing peptides make up approximately 50 percent of protein digests.

The Agilent Lys Tag 4H kit features a reagent for derivatization of lysine-containing peptides. Treatment or "tagging" with the reagent increases the detectability of lysine peptides as much as 20 times relative to untreated ones, resulting in greater protein sequence and peptide coverage. The MS spectra generated from tagged peptides are much simpler and more easily interpretable than those of untreated fragments. These properties improve the speed and accuracy of database matching and allow for more confident peptide sequencing of previously unknown proteins.

In validation experiments, Sue Francis and Professor Simon Gaskell at the Michael Barber Centre for Mass Spectrometry, University of Manchester Institute of Science and Technology, demonstrated that the reagent greatly increased sequence coverage for protein sequencing. For example, the researchers detected 17 peptides in one sample with lysine tagging compared to only 6 peptides without it.

"The kit is easy to use and dramatically improves MALDI-MS signals of lysine-containing peptides," said Professor Terry Lee of the Beckman Research Institute at the City of Hope. The kit protocol is a simple, one-step process. By facilitating the use of MALDI-MS, the kit also enables researchers to analyze proteins using faster, simpler and less expensive equipment than conventional liquid chromatography/mass spectrometry techniques.

"The introduction of this kit addresses inefficiencies in sample preparation, which remains a key bottleneck in the proteomics workflow," said Fran DiNuzzo, vice president and general manager of Agilent's Integrated Biology Solutions business. "Along with the Multiple Affinity Removal System, the Lys Tag 4H kit will be an indispensable tool for proteomics researchers who want to increase the speed, productivity and dynamic range of protein analysis."

The Lys Tag 4H reagent kit contains 10 vials with 20 mg of reagent each, sufficient for more than 200 reactions. An accessories kit is also available for tryptic digestion of proteins before reagent use and for cleanup of peptides afterward.


The Agilent Lys Tag 4H reagent kit is available for order now. More information is available at

About Agilent Technologies

Agilent Technologies Inc. (NYSE:A) is a global technology leader in communications, electronics, life sciences and chemical analysis. The company's 28,000 employees serve customers in more than 110 countries. Agilent had net revenue of $6.1 billion in fiscal year 2003. Information about Agilent is available on the Web at

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Christina Maehr
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