Metallo-phosphoesterase involved in phosphate metabolism. Acid phosphatase activity with phosphoenolpyruvate, inorganic pyrophosphate, phenyl-phosphate and p-nitrophenyl-phosphate as the most effective substrates. No activity with phytic acid, phosphocholine or bis-p-nitrophenyl-phosphate. Has a peroxidase activity at alkaline pH. a phosphate monoester + H2O = an alcohol + phosphate 2 a phenolic donor + H2O2 = 2 a phenolic radical donor + 2 H2O Binds 1 Fe cation per subunit. Binds 1 zinc ion per subunit. Activated by Mg(2+), Co(2+), Mn(2+) and Ba(2+). Inhibited by Fe(2+), Cu(2+), Zn(2+), NaF, molybdate, arsenate, vanadate and inorganic phosphate. No effect of tartrate, Asp, Gln, glutathione, Asn, ascorbic acid and phosphite. Optimum pH is 5.6 for the phosphatase activity and 8.8 for the peroxidase activity. Homodimer. Expressed in roots, stems, leaves, flowers and siliques. Not induced at the transcription level by phosphate starvation, but accumulation of the protein in starved shoots. Glycosylated. Belongs to the metallophosphoesterase superfamily. Purple acid phosphatase family.