Partial Purification and Kinetic Properties of Polygalacturonase from Solanum macrocarpum L. Fruit
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Background and Objective: Polygalacturonase [Poly (1, 4-"-D-galacturonide) glucanohydrolase, E.C 3.2.1.15] is a subclass of pectinase
that hydrolyzes the glycosidic linkages between galacturonic acid residues in polygalacturonans. Solanum macrocarpum ripening
prompts pectinase production. The objective of this study was to examine the kinetic properties of polygalacturonase from Solanum
macrocarpum L. fruit. Methodology: The enzyme was partially purified by ammonium sulphate precipitation and gel filtration. Protein
content, polygalacturonase activity and kinetic parameters were determined. Results: The protein content and polygalacturonase activity
of the fruit juice extracts were 0.63±0.02 mg mLG1 and 45.96±6.31 U mgG1 protein, respectively. A 1.7 and 108.3 fold increase in enzyme
activity was achieved by ammonium sulphate precipitation and gel filtration, respectively. The enzyme had a Vmax of
76.92 unit mgG1 protein and Km of 0.92 mg mLG1. The pH profile of the enzyme showed three activity peaks at 3.0, 5.5 and 7.0. The enzyme
was most active at pH 3.0 and showed optimal activity at 30EC. Rapid release of product was observed within the first 20 min of enzyme
incubation. The Zn2+, Ca2+, Mn2+, Pb2+, Fe2+, Cu2+ and EDTA exhibited inhibitory effect on polygalacturonase activity whereas Mg2+ had
stimulatory effect on the enzyme. Conclusion: It was concluded that the fruit of Solanum macrocarpum is a rich source of
polygalacturonase. The enzyme is favourably comparable with that of a fungi source and could be further exploited for commercial
production of the enzyme
Keywords
QH301 Biology, S Agriculture (General)