This family of regulatory proteins has ADP-dependent kinase and inorganic phosphate-dependent pyrophosphorylase activity [1-3].

1: Cloning and expression of maize-leaf pyruvate, Pi dikinase regulatory protein gene. Burnell JN, Chastain CJ; Biochem Biophys Res Commun. 2006;345:675-680. PMID:16696949

2: The pyruvate, orthophosphate dikinase regulatory proteins of Arabidopsis possess a novel, unprecedented Ser/Thr protein kinase primary structure. Chastain CJ, Xu W, Parsley K, Sarath G, Hibberd JM, Chollet R; Plant J. 2008;53:854-863. PMID:17996018

3: Cloning and characterization of Escherichia coli DUF299: a bifunctional ADP-dependent kinase--Pi-dependent pyrophosphorylase from bacteria. Burnell JN; BMC Biochem. 2010;11:1. PMID:20044937