Recent Advances and Applications of Polyphosphate Kinase 2 Class III (PPK2-III)

Enzymatic synthesis of natural or modified nucleoside triphosphates (NTPs) with significant advantages has emerged as a promising alternative to chemical synthesis. Polyphosphate kinase (PPKs) are a class of enzymes responsible for reversible polyphosphate (polyP) synthesis (PPK1) and nucleotides phosphorylation (PPK2) by utilizing cost effective and stable polyP as phosphate donors. Recently, PPK2 class III (PPK2-III) has been increasingly utilized as a single bifunctional enzyme for nucleotide phosphorylation either from nucleoside monophosphate or diphosphate substrates. The applications of PPK2-III extend to widespread use in adenosine-5'-triphosphate (ATP) regeneration and modified NTP synthesis, which significantly facilitated the biosynthesis of high-value pharmaceuticals and nucleic acid synthesis. Herein, we summarized the properties, functions and well-established applications of currently reported PPK2-III enzymes.