Protein complex set is gathered from three sources: MIPS (Mewes et al., 2004), SGD (Cherry et al., 1998) database and Aloy et al. (2004). By means of experiments, Aloy et al. (2004) selected 102 complexes from 232 yeast complexes characterized by tandem affinity purification (TAP). Those complexes that yielded more than 0.1 mg of protein form 2 L culture were selected. The final set contains 425 complexes and 1970 proteins in total.