Table 2. Significantly recurring network motifs.

interaction A	interaction B	interaction C
cleavage reaction	cleavage reaction	cleavage reaction
covalent binding	cleavage reaction	cleavage reaction
phosphorylation reaction	cleavage reaction	cleavage reaction
phosphorylation reaction	phosphorylation reaction	cleavage reaction
covalent binding	covalent binding	covalent binding
phosphorylation reaction	covalent binding	covalent binding
methylation reaction	methylation reaction	covalent binding
phosphorylation reaction	phosphorylation reaction	phosphorylation reaction