Purification and properties of peroxidase from Pinus pinaster needles

Peroxidase (Ec 1.11.1.7) was purified from needles of Pinus pinaster to apparent homogeneity by DE-52 cellulose chromatography with a final recovery of enzyme activity of about 85%. The purified enzyme (A402/A275 = 1.05) had a specific activity of about 948 U/mg of protein and ran as a single protein band both on SDS-PAGE and native PAGE with Mr of 37,000 and 151,000, respectively. Both native PAGE and isoelectric focusing gels of the purified enzyme were stained for activity which coincided with the protein band. The pI of the purified enzyme was found to be 3.2 by isoelectric focusing on an ultrathin polyacrylamide gel. The enzyme has an optimum pH of activity of 5.0 and temperature optimum of 30 degrees C. Stability studies of the enzyme as a function of pH and temperature suggest that it is most stable at pH 5.0 and 0-40 degrees C, respectively.