A specific term is needed in order to annotate (local) parameters in SBML as the effective catalytic rate keff (see the definition in the paper http://identifiers.org/pubmed/24084808 and its sublement). This is a parameter that describes the lumped turnover rate of a reaction to convert substrates to products. It is expressed in the units per time.
Anonymous
created SBO:0000611 (effective catalytic rate) as a child of kinetic constant (SBO:0000009).