Protein chips can be used to study a variety of processes, including protein-protein interactions, protein expression, and small-molecule protein binding. For example, Michael Snyder's group at Yale University has developed protein chips to enable analysis of virtually all 6,000 proteins in yeast.

Until recently, protein chips were produced by a handful of biotech companies, most of which had

High-throughput proteomics simplified with PerkinElmer's Protein Array Workstation.

BD Clontech is offering what may be the first off-the-shelf, antibody-based chips for protein expression profiling — the Ab Microarray. The chip contains 378 monoclonal antibodies immobilized onto a glass surface. Researchers can use the chips, which cost about $2,000 for two, to compare the range of proteins found in two samples.

Clontech won't be alone in this market for long. "You will start seeing more companies offering preprinted arrays, probably later this summer," says Robert Cavallo, product manager for PerkinElmer Life Science's Protein Microarrays. PerkinElmer is also developing protein chips, as well as other tools that should make it easier for the average scientist to get into the field. "We have made a big commitment to this area," says Cavallo.

In September, PerkinElmer will launch its Protein Array Workstation, which automates protein chip studies. It can accommodate two low-volume samples per slide, and carries out the required chemistries.

But handling proteins is a lot more difficult than dealing with DNA, Cavallo points out, and researchers will want to do more complex studies, such as "sandwich" assays that involve applying the sample to the chip, and then adding a detection antibody. "I think people will end up using both DNA chips and protein chips," Cavallo says. "You can get different information from each one."

—Malorye Branca