ISSN:
1750-3841
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
An endo-polygalacturonase (RAPG) from Rhizopus arrhizus grown on rotted apricot has been purified and characterized. Through dialysis, ammonium sulfate fractionation, and successive chromatography on DEAE-cellulose, Sephadex G-100 and Sephadex G-75 columns, a 274-fold purification was achieved. RAPG was stable at pH 3.8–6.5. Its optimum activity was at pH 5.0. The activation energy (Ea) was 11.9 Kcal/mole. The Q1 0 value was 2.01 between 20° and 30°C. RAPG has a Vmax at 1.430 μmoles reducing product/min, and Km at 0.054% pectic acid (DP = 70). Both sodium and potassium ions stimulated RAPG activity in the 0.05–0.10M range. Tannic acid was an effective inhibitor, while chlorogenic, caffeic, p-coumaric and gallic acids were not. The molecular weight of RAPG was 30,270 by SDS-gel electro-phoresis. Both viscosity drop and thin layer chromatography of the end products study proved that RAPG performed a random mechanism in the depolymerization process. RAPG also showed a synergistic effect when tomato pectinesterase was added to the reaction mixture with pectin as the substrate.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2621.1978.tb02402.x
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