Abstract
Any set of connected enzyme reactions constitute a network. Contrary to most networks studied so far (for instance networks of social connections) metabolic networks are open structures with an input and an output of matter. As such they possess some properties that are unique when compared to closed networks.
Keywords: Node degree, Random graph, Diameter of a graph, Closed network, Open network, Meta-network, Conditional probabilities of binding for a network, Information consumed, or produced, by a node, Open character of a network and probabilities of occurrence of its nodes, Thermodynamic constraints upon running from a node to another one.