Purification and characterization of an exo-polygalacturonase from Pycnoporus sanguineus |
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Authors: | Emma N Quiroga Melina A Sgariglia César F Molina Diego A Sampietro José R Soberón Marta A Vattuone |
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Institution: | aCátedra de Fitoquímica, Instituto de Estudios Vegetales “Dr. A.R. Sampietro”, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, (4000) San Miguel de Tucumán, Argentina;bConsejo Nacional de Investigaciones Científicas y Técnicas, Argentina;cEstación Experimental Agroindustrial “Obispo Colombres”, Tucumán, Argentina |
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Abstract: | The present work describes the purification and characterization of a novel extracellular polygalacturonase, PGase I, produced by Pycnoporus sanguineus when grown on citrus fruit pectin. This substrate gave enhanced enzyme production as compared to sucrose and lactose. PGase I is an exocellular enzyme releasing galacturonic acid as its principal hydrolysis product as determined by TLC and orcinol-sulphuric acid staining. Its capacity to hydrolyze digalacturonate identified PGase I as an exo-polygalacturonase. SDS-PAGE showed that PGase I is an N-glycosidated monomer. The enzyme has a molecular mass of 42 kDa, optimum pH 4.8 and stability between pH 3.8 and 8.0. A temperature optimum was observed at 50–60 °C, with some enzyme activity retained up to 80 °C. Its activation energy was 5.352 cal mol−1. PGase I showed a higher affinity towards PGA than citric pectin (Km = 0.55 ± 0.02 and 0.72 ± 0.02 mg ml−1, respectively). Consequently, PGase I is an exo-PGase, EC 3.2.1.82. |
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Keywords: | Characterization Exo-polygalacturonase Purification Pycnoporus sanguineus |
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