On the iTRAQ

Applied Biosystems www.appliedbiosystems.com, based in Foster City, Calif., has introduced a new family of reagents for multiplexed LC/MS experiments. The iTRAQ reagents enable comparison of protein expression in multiple samples, such as those of normal, diseased, and drug-treated states, and have the ability to detect posttranslational modifications, the company claims. The company has also released Pro QUANT software for automated analysis of LC/MS data collected using the reagents.

ICAT reagents, Applied Biosystems' first foray into multiplexed LC/MS sample preparation, attach to cysteine residues. The new iTRAQ reagents are amine-specific and thus tag all peptides (not just those containing cysteine), thereby expanding proteome coverage.

Potential applications include membrane-protein studies, target-protein quantitation, and biomarker discovery and validation. Richard A. Caprioli, director, Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, recently purchased the kit. "It seems like a straightforward approach involving well-known tools put into a very nice package," he says. ...