A novel 35 kDa frog liver acid metallophosphatase

• Published in: Biochimica et biophysica acta Vol. 1431; no. 1; pp. 199 - 211
• Main Authors: Szalewicz, Agata, Radomska, Barbara, Strzelczyk, Barbara, Kubicz, Aleksandra
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 12.04.1999
• Subjects: Acid phosphatase; Acid Phosphatase - chemistry; Animals; Apoenzymes - chemistry; Cations - pharmacology; Chelating Agents - pharmacology; Divalent metal cation; Electron Spin Resonance Spectroscopy; Enzyme Activation; Enzyme Reactivators; Enzyme Stability; Frog liver; Liver - enzymology; Metalloenzyme; Metallophosphatase; Metals - analysis; Metals - pharmacology; Molecular Weight; Rana esculenta; BSA, bovine serum albumin; pNPP, p-nitrophenyl phosphate; BCA, bicinchoninic acid; Metalloenzyme; HMW AcPase, high molecular weight acid phosphatase; LMW AcPase, lower molecular weight acid phosphatase; OP, 1,10-phenanthroline ( o-phenanthroline); DTT, dithiothreitol; PAP, purple acid phosphatase; PMSF, phenylmethylsulfonyl fluoride; Con A, concanavalin A; EDTA, ethylenediaminetetraacetate disodium salt; Metallophosphatase; Divalent metal cation; Frog liver; Acid phosphatase; AcPase, acid phosphatase; TRAP, tartrate-resistant acid phosphatase
• DOI: 10.1016/S0167-4838(99)00029-1
• ISSN: 0167-4838; 0006-3002

The lower molecular weight (35 kDa) acid phosphatase from the frog ( Rana esculenta) liver is a glycometalloenzyme susceptible to activation by reducing agents and displaying tartrate and fluoride resistance. Metal chelators (EDTA, 1,10-phenanthroline) inactivate the enzyme reversibly in a time- and temperature-dependent manner. The apoenzyme is reactivated by divalent transition metal cations, i.e. cobalt, zinc, ferrous, manganese, cadmium and nickel to 130%, 75%, 63%, 62%, 55% and 34% of the original activity, respectively. Magnesium, calcium, cupric and ferric ions were shown to be ineffective in this process. Metal analysis by the emission spectrometry method (inductively coupled plasma-atomic emission spectrometry) revealed the presence of zinc, iron and magnesium. The time course of the apoenzyme reactivation, the stabilization effect and the relatively high resistance to oxidizing conditions indicate that the zinc ion is crucial for the enzyme activity. The presence of iron was additionally confirmed by the visible absorption spectrum of the enzyme with a shoulder at 417 nm and by the electron paramagnetic resonance line of high spin iron(III) with g eff of 2.4. The active center containing only zinc or both zinc and iron ions is proposed. The frog liver lower molecular weight acid phosphatase is a novel metallophosphatase of lower vertebrate origin, distinct from the mammalian tartrate-resistant, purple acid phosphatases.