Purification and Some Properties of Pectinesterase from Fruits of a Miniature-Fruited Red Type Tomato

Abstract

A pectinesterase (E.C. 3.1.1.11, pectin pectylhydrolase) from the ripening stage of fruits of a miniature-fruited red type tomato (Mini-tomato) was purified 247 fold with yield of 26% by ammonium sulfate fractionation, affinity chromatography, and gel filtration. The molecular weight of the enzyme was found to be 15,000 by gel filtration and SDSPAGE. The optimum activity was at pH 7.0 and at 50°C. The enzyme was stable between pH 6 and 7 and at temperatures below 50°C. The K_m value was estimated to be 0.48% for citrus pectin as the substrate. Chelating reagents were the effective inhibitors of the enzyme.