The procedure of yeast proteome analysis using protein chip technology. The yeast ORFs were cloned into a double tagged yeast GAL1 expression vector via a recombination strategy and verified for correct identities by sequencing. Each pure plasmid construct was then reintroduced into a yeast strain for large- scale protein purification. Yeast cultures were grown in a 96-well format and induced by addition of galactose. After the high-throughput purification step, the purified proteins were aliquoted and stored in a glycerol buffer at ¨C80¡ãC before printing. Using a high precision microarrayer, 6566 protein samples can be double-spotted onto 80 slides in a single experiment.