This enzyme is a membrane protein and goes through an intermediate stage during the reaction where it is autophosphorylated with a phosphate group covalently linked to a basic amino acyl residue through an N-P bond.
[5] CYTH-like superfamily enzymes, which include polyphosphate polymerases, hydrolyze triphosphate-containing substrates and require metal cations as cofactors.
The name CYTH originated from the gene designation for bacterial class IV adenylyl cyclases (CyaB), and from thiamine triphosphatase (THTPA).
Class IV adenylate cyclases catalyze the conversion of ATP to 3',5'-cyclic AMP (cAMP) and PPi.
In the yeast protein, Syg1, the N-terminus directly binds to the G-protein beta subunit and inhibits transduction of the mating pheromone signal.
Similarly, the N-terminus of the human XPR1 protein binds directly to the beta subunit of the G-protein heterotrimer, leading to increased production of cAMP.
The SPX domains of the S. cerevisiae low-affinity phosphate transporters, Pho87 and Pho90, auto-regulate uptake and prevent efflux.
Members of this family include YidH of E. coli (TC# 9.B.51.1.1) which has 115 amino acyl residues and 3 TMSs of α-helical nature.