Abstract
A pectinesterase was purified from the culture filtrate of C. rolfsii IFO 6146 by a combination of salting out, gel filtration on Sephadex G-100 and chromatography on DEAE-Sephadex A-50, SP-Sephadex C-50 and hydroxylapatite. The purified enzyme was found to be homogeneous protein by ultracentrifugal analysis. The molecular weight of the purified enzyme was found to be about 37, 000 by the gel filtration. The enzyme was stable over the pH range of 1.1 to 10.0 and retained 90% of its activity when stored at pH 1.1 at 5°C for 72 hr. The maximum activity occurred at pH 2.5 to 4.5 at 45°C. The enzyme was fairly active at a very low pH (1.1) or low temperature (10°C). Hg2+ was a potent inhibitor. The enzyme was active not only on high molecular pectin methyl esters but also on low molecular esters. The high enzymatic activity at very low pH values and the unusual tolerance to hydrogen ions are characteristics of pectinesterase from C. rolfsii. The enzyme is one of the acid esterases.
