Instead of the hit-and-miss technology of the past, current biological research and a lot of drug discovery is being driven by the search for new molecules targeting disease-relevant proteins (Borisy et al., 2003; Shawver et al., 2002; Gibbs, 2000). In this approach, a specific protein is studied in vitro, in cells and in whole organisms, and evaluated as a drug target for a specific therapeutic indication (Gibbs, 2000; Lenz et al., 2000; Kalgutkar et al., 2000). The historical paradigm, 'one-drug-one-target dogma', has resulted in the identification of many effective chemical molecules that affect specific proteins, providing valuable reagents for both biology and medicine. One example is the recently FDA-approved drug Avastin, a recombinant humanized antibody designed to bind to and inhibit Vascular Endothelial Growth Factor (VEGF) in tumour angiogenesis (Nanda and St Croix, 2004). Benefiting from the advancement of biology and chemistry, the world market of drug products has increased tremendously over the past decade, from US $180 billion in 1990 to US $430 billion in 2001 (RGPI, 2002). IMS Health, a well-known information company of pharmaceutical industry, anticipated that the annual sales of drug products would reach US $587.9 billion by the year of 2005, with an average growth rate of 7.8%, much higher than the average growth rate of the global economy (2.4%) (RGPI, 2002).