Biochemical characterization of a peroxidase isolated from Caribbean plant: Euphorbia cotinifolia

A Caribbean copper plant peroxidase (CCPP) is purified from the latex of Euphorbia cotinifolia, using anion exchange chromatography. The molecular mass and isoelectic point of the enzyme is 43.11 kDa and pH 8.1 respectively. The peroxidase is found to be sensitive towards general phenolic substrates like guaiacol, pyrogallol, a-aminopterin, phloroglucinol, o-phenelenediamine and dianisidine dihydrochloride. The substrate specificity of CCPP was distinct from that of other peroxidases, and the best substrate for CCPP was guaiacol at pH 6.0 and 50 degrees C. Sucrose and Ca(2+) enhance the activity whereas the activity is significantly inhibited by NaN(3) and Na(2)SO(3). The strong absorption at 650 nm reveals the presence of Cu ions as a prosthetic group. Spectroscopic studies reveal that CCPP has high alpha-helicity. The enzyme was found to be very stable at room temperature and retained more than 80% activity even after a period of 2 months and was stable for more than 6 months at 4 degrees C without any additive or preservative. Adequate amount of latex, easy purification method, broad substrate specificity, and high stability against pH, temperature, chaotrophs and organic solvents makes this enzyme a potential candidate in biotechnological and industrial applications. (C) 2011 Elsevier Ltd. All rights reserved.