Inorganic pyrophosphatase 1 (PPA1)

Inorganic pyrophosphatase 1 (PPA1) is a cytosolic enzyme (belonging to the soluble pyrophosphatase family) that catalyzes the highly exergonic hydrolysis of inorganic pyrophosphate (PPi) into two molecules of orthophosphate (Pi)[1][2]. This reaction is fundamental for maintaining the balance of phosphate compounds in cells, coupling with multiple biosynthetic processes—such as amino acid activation, nucleotide biosynthesis, DNA polymerization, lipid metabolism, and calcium homeostasis[2][1]. PPA1 is widely expressed in human tissue and is encoded on chromosome 10[2]. Structurally, human PPA1 forms a conserved dimeric protein with a catalytic domain dependent on divalent cations (e.g., Mg2+) for activity[1]. PPA1 is highly overexpressed in several tumor types and implicated in the proliferation, invasion, metastasis, and apoptosis suppression of malignancies, primarily via modulation of the JNK/p53, Wnt/β-catenin, and PI3K/AKT/GSK-3β signaling pathways[1]. Its expression also correlates with metabolic conditions related to abnormal PPi and Pi balance, and has emerging relevance in neurological development and systemic metabolic diseases[1]. Currently, PPA1 is considered a potential biomarker for cancer prognosis, though no approved drugs target it directly; ongoing research examines its value both as a diagnostic and therapeutic target[1][2].

Other names

Inorganic pyrophosphataseIOPPPPPPPaseSID6-8061PpasePP1Pyrophosphate phospho-hydrolasecytosolic inorganic pyrophosphataseinorganic diphosphatase 1HEL-S-66pdiphosphate phosphohydrolasepyrophosphatase (inorganic) 1pyrophosphatase 1epididymis secretory sperm binding protein Li 66p

Hydrolysis of PPi to Pi (core catalytic function); Modulation of JNK/p53, Wnt/β-catenin, and PI3K/AKT/GSK-3β signaling pathways in tumor biology; Inhibition of NAD+ metabolism (associated with cell cycle arrest and autophagy); Regulation by microRNAs (e.g., miR-545-3p)