Table 2. Scaling exponents characterizing the studied cellular networks.

	Transcription		Metabolic		Protein Interaction
Exponent	E. coli	S. cerevisiae	E. coli	S. cerevisiae	S. cerevisiae
γ	2.1 ± 0.3	2.0 ± 0.2	2.0 ± 0.4	2.0 ± 0.1	2.4 ± 0.4
α	1.0 ± 0.2	1.0 ± 0.2	0.8 ± 0.3	0.7 ± 0.3	1.3 ± 0.5
β
Meas.	1.0 ± 0.2	0.8 ± 0.2	1.1 ± 0.2	1.4 ± 0.2	0.7 ± 0.2
Pred.	0.97	0.95	1.2	1.3	0.7
δ
Meas.	2.1 ± 0.2	2.2 ± 0.2	1.8 ± 0.2	1.7 ± 0.2	2.3 ± 0.2
Pred.	2.0	1.9	1.8	1.8	3.0

The γ and α exponents for each of the studied cellular networks, determined from a direct fit to the P(k) and C(k) functions of the undirected network representation (see supporting information). We also provide the measured and predicted values of the β and δ exponents, characterizing the average number of triangle (3,3) motifs in which a node with k links participates [T(k) ∼ k^β] and the distribution of the number of triangle motifs in which a node participates [P(T) ∼ T^-δ].