May regulate the electrogenic sodium/bicarbonate cotransporter SLC4A4 activity and Mg(2+)-sensitivity. On the contrary of its homolog AHCYL1, does not regulate ITPR1 sensitivity to inositol 1,4,5-trisphosphate (By similarity). H2O + S-adenosyl-L-homocysteine = adenosine + L-homocysteine Binds 1 NAD(+) per subunit. Amino-acid biosynthesis; L-homocysteine biosynthesis; L-homocysteine from S-adenosyl-L-homocysteine: step 1/1. Homotetramer. Forms heteromultimers with AHCYL1 (via the C-terminal region). Interacts with ITPR1; with lower affinity than AHCYL1 and maybe via ITPR1 (By similarity). Interacts with SLC4A4 (PubMed:24472682). Interacts with ZCCHC4 (By similarity). Associates with membranes when phosphorylated, probably through interaction with ITPR1. Expressed in parotid and acinar cells (at protein level). Phosphorylated during neuronal differentiation at the LISN domain. Belongs to the adenosylhomocysteinase family.