Characterizing Enzymes of the Diphosphoinositol Polyphosphate Phosphohydrolase (DIPP) Family.

The diphosphoinositol polyphosphate phosphohydrolases are a subset of the Nudix hydrolase family of enzymes. As such, they metabolize a wide range of substrates, including diphosphoinositol polyphosphates (inositol diphosphates, inositol pyrophosphates), dinucleotide phosphates, nucleosides as well as 5-phosphoribosyl 1-pyrophosphate and inorganic polyphosphate. Here, we describe protocols to optimize these enzymes, with consideration to buffer composition and sample preparation and how to analyze the metabolism of these substrates using high-performance liquid chromatography, giving advice where pitfalls are commonly encountered.