https://doi.org/10.1351/goldbook.A00240
@E02159@ which contain regions to which small, regulatory molecules (cf. @E01901@) may bind in addition to and separate from @S06083@ binding sites. On binding the @E01901@, the catalytic activity of the enzyme towards the substrate may be enhanced, in which case the @E01901@ is an @A00104@, or reduced, in which case it is an @I03035@.