Phosphatase that has a high activity toward phosphoethanolamine (PEA) and phosphocholine (PCho) (By similarity). Involved in the generation of inorganic phosphate for bone mineralization (PubMed:17227223). Acts in a non-redundant manner with PHOSPHO1 in skeletal mineralization: while PHOSPHO1 mediates the initiation of hydroxyapatite crystallization in the matrix vesicles (MVs), ALPL/TNAP catalyzes the spread of hydroxyapatite crystallization in the extracellular matrix (PubMed:26457330, PubMed:20684022). H2O + phosphoethanolamine = ethanolamine + phosphate H2O + phosphocholine = choline + phosphate Localizes to special class of extracellular vesicles, named matrix vesicles (MVs), which are released by osteogenic cells. Has a 120-fold higher level of expression in bone compared with a range of soft tissues. Mice display growth plate abnormalities, spontaneous fractures, bowed long bones, osteomalacia and scoliosis in early life (PubMed:20684022). Primary cultures of tibial growth plate chondrocytes and chondrocyte-derived matrix vesicles (MVs) show reduced mineralizing ability, and plasma samples show reduced levels of Alpl/Tnap and elevated plasma diphosphate (inorganic pyrophosphate; PPi) concentrations (PubMed:20684022). Mice lacking both Phospho1 and Alpl/Tnap show a complete absence of skeletal mineralization, leading to perinatal lethality (PubMed:20684022). Belongs to the HAD-like hydrolase superfamily. PHOSPHO family.