Purification and enzymatic properties of a peroxidase from leaves of Phytolacca dioica L. (Ombú tree).
A peroxidase (PD-cP; 0.47 mg/100 g leaves) was purified from autumn leaves of Phytolacca dioica L. and characterized. PD-cP was obtained by acid precipitation followed by gel-filtration and cation exchange chromatography. Amino acid composition and N-terminal sequence of PD-cP up to residue 15 were similar to that of Spinacia oleracea (N-terminal pairwise comparison showing four amino acid differences). PD-cP showed a molecular mass of approx. 36 kDa by SDS-PAGE, pH and temperature optima at 3.0 and 50.0°C, respectively and seasonal variation. The Michaelis-Menten constant (K(M)) for H(2)O(2) was 5.27 mM, and the velocity maximum (V(max)) 1.31 nmol min(-1), while the enzyme turnover was 0.148 s(-1). Finally, the presence of Ca(2+) and Mg(2+) enhanced the PD-cP activity, with Mg(2+) 1.4-fold more effective than Ca(2+)
Dipartimento di Scienze della Vita, Seconda Universitá di Napoli, Caserta, Italy.
Vincenzo
V
Guida
Giovanna
G
Criscuolo
Rachele
R
Tamburino
Livia
L
Malorni
Augusto
A
Parente
Antimo
A
Di Maro
D000595:Amino Acid Sequence; D002118:Calcium / Q000737:chemistry; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000737:chemistry; D008969:Molecular Sequence Data; D009195:Peroxidase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D029603:Phytolacca / Q000201:enzymology*; D018515:Plant Leaves / Q000201:enzymology; D013696:Temperature
D009195:Peroxidase; D008274:Magnesium; D002118:Calcium