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Table 1 Properties of PPI networks

From: Evidence of probabilistic behaviour in protein interaction networks

Network Number of proteins Number of interactions r* θ γ (× 10-5) γ(cal) (× 10-5)
H. sapiens 9263 34564 0.99 1.00 ± 0.02 1.49 1.45
D. melanogaster 6736 20308 0.99 1.01 ± 0.02 2.25 2.46
Yeast       
   - DIP 4617 16311 0.99 1.02 ± 0.02 2.98 3.07
   - CORE 2449 5579 0.99 1.03 ± 0.06 8.41 8.97
   - Y2H 3277 4393 0.99 1.15 ± 0.08 7.22 11.4
E. coli 1473 5709 0.97 1.06 ± 0.04 6.09 8.79
Worm       
   - Y2H 2624 3967 0.98 1.08 ± 0.07 9.59 12.6
   - CORE 727 814 0.99 1.03 ± 0.09 53.5 61.7
P. falciparum 1304 2745 0.99 0.99 ± 0.05 18.0 18.3
  1. *Pearson correlation coefficient for test of association between P(k1, k2) and k1k2, where P(k1, k2) is the probability of interaction between two proteins of degrees k1 and k2.
  2. Fitted values (from the Log-Log plots in Figure 1) occurring in the expression P(k1, k2) = γ(k1k2)θ. θ is given with 99% confidence intervals.
  3. Prediction of γ via γ(cal) = Ei<j(k i k j ), where E is the number of interactions in the network and the summation is over all pairs of proteins.