Figure 1. Domain organization of the subunit sequences of some of the PFK-2/FBPase-2 isoenzymes.

The N-terminal PFK-2 domain is shown in red and the C-terminal FBPase-2 domain is in blue. Numbering refers to the individual isoenzyme sequences. The black box in the PFK-2 domain indicates the position of the glycine-rich loop in the nucleotide-binding fold with the signature G(X)₄GKT/S. The black box in the FBPase-2 domain contains the active site histidine in the RHG motif which has become mutated in some of the monofunctional isoforms. Phosphorylation sites for protein kinases are indicated in red (see text).