title: Purification, primary structure, and properties of Euphorbia characias latex purple acid phosphatase.
abstract: A purple acid phosphatase was purified to homogeneity from Euphorbia characias latex. The native protein has a molecular mass of 130 ± 10 kDa and is formed by two apparently identical subunits, each containing one Fe(III) and one Zn(II) ion. The two subunits are connected by a disulfide bridge. The enzyme has an absorbance maximum at 540 nm, conferring a characteristic purple color due to a charge-transfer transition caused by a tyrosine residue (Tyr172) coordinated to the ferric ion. The cDNA nucleotide sequence contains an open reading frame of 1392 bp, and the deduced sequence of 463 amino acids shares a very high degree of identity (92-99%) to other purple acid phosphatases isolated from several higher plants. The enzyme hydrolyzes well p-nitrophenyl phosphate, a typical artificial substrate, and a broad range of natural phosphorylated substrates, such as ATP, ADP, glucose-6-phosphate, and phosphoenolpyruvate. The enzyme displays a pH optimum of 5.75 and is inhibited by molybdate, vanadate, and Zn2+, which are typical acid phosphatase inhibitors.
authors.affiliation: Department of Applied Sciences in Biosystems, University of Cagliari, Cagliari, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Pintus
authors.forename: D
authors.initials: D
authors.lastname: Spano
authors.forename: S
authors.initials: S
authors.lastname: Corongiu
authors.forename: G
authors.initials: G
authors.lastname: Floris
authors.forename: R
authors.initials: R
authors.lastname: Medda
mesh_terms: D000135:Acid Phosphatase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D000595:Amino Acid Sequence; D028481:Euphorbia / Q000201:enzymology*; D006023:Glycoproteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000737:chemistry; D008969:Molecular Sequence Data; D011485:Protein Binding; D013379:Substrate Specificity
chemical_list: D006023:Glycoproteins; D008670:Metals; C091137:purple acid phosphatase; D000135:Acid Phosphatase