Protein kinase substrate profiling with a high-density peptide microarray.

We describe a powerful peptide microarray for profiling protein kinase substrates that combines the merits of chemoselective immobilization of peptides to achieve high density spots with the advantages of fluorescence-based analysis of phosphorylation for nonhazardous detection. For detection of on-chip phosphorylation, we used a fluorescence-labeled antiphosphotyrosine antibody to detect phosphotyrosine and a biotinylated Phostag, which was subsequently bound with a fluorescence-labeled streptavidin for phosphoserine/threonine. More than 290 kinds of Tyr peptides and over 1,100 kinds of Ser/Thr peptides were chemoselectively immobilized onto a glass surface in a high-density format to profile a panel of protein kinases, including c-Src, c-Abl, EGFR, JNK1, ERK2, p38α, and PKA.

A quantitative peptide array for evaluation of protein kinase activity.

Peptide array, which is known as an emerging technology, has been developed for identification of protein kinase activity. For this purpose, the ability of quantitative analysis is very important because the absolute change in protein kinase activity is critical for the determination of cellular function. Here we report an original type of peptide array for quantitative evaluation of protein kinase activity by fluorescence imaging.

A peptide microarray for the detection of protein kinase activity in cell lysate.

DNA microarray enables the analysis of DNA or mRNA expression levels, but it has not been possible to completely understand life using obtained information. Consequently, protein or peptide arrays have attracted much interest. Since the development of a practical protein microarray is still far away in light of handling difficulties, the peptide microarray is a promising tool for analyzing protein functions.

Mass-tag technology for monitoring of protein kinase activity using mass spectrometry.

Monitoring of intracellular protein kinase activity is very important for fields involving diagnosis and drug screening. However, current methods, such as radiometry using (32)P, or ELISA, are laborious and time-consuming. We have developed high-throughput assay system of protein kinase activity using mass-tagged substrate peptide probes and mass spectrometry.