What are the definitions of the relationship types?

Binding:  Physical interaction between molecules.

Chemical Reaction:  Symbolizes either enzyme catalyzed or spontaneous chemical reaction, i.e. transformation of one set of Small Molecules into another.  Usually must  have at least one substrate show with the link incoming to control and one product shown with the link outgoing from control.  Enzyme is shown as undirected link between Functional Class or Protein entity and control.  

DirectRegulation:  Indicates that the regulator influences the target activity by physically interacting with it.

Expression:  Indicates that the regulator changes the protein level of the target, by means of regulating its gene expression or protein stability.

MolSynthesis:  Indicates that the regulator changes the concentration of the target.  Usually Small Molecule is a target in MolSynthesis

MolTransport:  Indicates that the regulator changes the localization of the target.  Describes events of molecular translocation, export, import or release.

PromoterBinding:  Indicates that the regulator binds the promoter of the target.

ProtModification:  Indicates that the regulator molecule changes the protein modification of the target molecule.  Usually indicates the direct interaction, i.e. the regulator catalyses the chemical modification reaction.

Regulation:  Indicates that the regulator changes the activity of the target.  The mechanism of the regulation is either unknown or has not been specified in the sentence describing the relation.