ABSTRACT
The construction of protein interaction networks focusing on the assembly of protein complexes may give an idea of the problems inherent in such an approach, particularly where the faithful proof of interactions is concerned. By combining the traditional reductionist methodology with a holistic approach, systems biology aims at an understanding of complex systems in a quantitative and predictable way. Although many kinetic parameters have been determined, especially in biochemistry, it is still difficult to link these measurements of the isolated enzyme to the situation in vivo. An in-depth investigation of the structure and dynamics of biological systems is expected to have far-reaching practical consequences, for instance in medicine, agriculture, and environmental protection. For a protein network, a scale-free topology means that most proteins interact with only a few partners, whereas a few proteins exhibit a high number of interactions.
