Structural analysis of these proteins has revealed a common core of 155 residues: the core comprises 5 alpha-helices and 11 beta-strands, and includes residues essential for metal binding and catalysis. While the core has been conserved presumably to impart catalytic function, the loops and regions of structure outside the core have evolved unique regulatory domains [PMID:7761465].

An interesting property of the enzymes of this family is their sensitivity to Li⁺ at levels achieved in patients undergoing therapy for manic depression. The targets and mechanism of action of Li⁺ are unknown, but overactive inositol phosphate signalling may account for symptoms of the disease [PMID:2553271]. It has been proposed that these Li⁺-sensitive proteins could represent targets for Li⁺ in manic depressive disease [PMID:7761465]. Recently, the fold of fructose 1,6-bisphosphatase (FBPTASE) was noted to be identical to that of MPTASE [PMID:8382485]. FBPTASE is a critical enzyme in the gluconeogenic pathway that removes the 1-phosphate from fructose 1,6-bis- phosphate to form fructose 6-phosphate [PMID:2159755, PMID:3008716]. FBTASE also requires metal ions for catalysis (Mg²⁺ and Mn²⁺ being preferred) and the enzyme is potently inhibited by Li⁺. 1PTASE, MPTASE and FBPTASE share a sequence motif (Asp-Pro-Ile/Leu-Asp- Gly/Ser-Thr/Ser) which has been shown to bind metal ions and participate in catalysis. This motif is also found in the distantly-related fungal, bacterial and yeast MPTASE homologues. It has been suggested that these proteins define an ancient structurally conserved family involved in diverse metabolic pathways, including inositol signalling, gluconeogenesis, sulphate assimilation and possibly quinone metabolism [PMID:7761465].