A contribution to the characterization of protopectinase SE, an endopolygalacturonase with pectin-releasing activity from geotrichum klebahnii
Hydrolysis of polygalacturonic acid (1.8 g.L<sup>−1</sup> ) with 1.25 mg.L<sup>−1</sup> of a commercial preparation (Pectinase SE from Shikibo Ltd., Japan) containing protopectinase SE (PPase-SE) activity for 80 min released a reducing power equivalent to ≈ 400 mg.L<sup>−1</sup> of galacturonic acid...
| Autores: | ; ; |
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| Tipo de documento: | Artículo |
| Estado: | Published version |
| Fecha de publicación: | 2014 |
| País: | Argentina |
| Institución: | UNLP |
| Repositorio: | SEDICI (UNLP) |
| Lenguaje: | Inglés |
| OAI Identifier: | oai:sedici.unlp.edu.ar:10915/98532 |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/98532 |
| Nivel de acceso: | Acceso abierto |
| Palabra clave: | Ingeniería Química Endo-poligalacturonase Kinetic characterization Metal inhibition Endo-poligalacturonasa Caracterizacion cinética Inhibición metálica |
| Sumario: | Hydrolysis of polygalacturonic acid (1.8 g.L<sup>−1</sup> ) with 1.25 mg.L<sup>−1</sup> of a commercial preparation (Pectinase SE from Shikibo Ltd., Japan) containing protopectinase SE (PPase-SE) activity for 80 min released a reducing power equivalent to ≈ 400 mg.L<sup>−1</sup> of galacturonic acid monohydrate, yielding oligogalacturonates with an average polymerization degree of around 4. Thermostability of PPase-SE was positively affected by enzyme concentration. Enzyme activity of a solution containing 12.5 mg.L<sup>−1</sup> of Pectinase SE in 20 mM sodium acetate buffer, pH 5.0, quickly dropped to less than 20 % after 80 s of vortexing. Enzyme pre-incubation (37°C, 30 min) with Ca<sup>2+</sup>, Mg<sup>2+</sup>, Co<sup>2+</sup>, Cu<sup>2+</sup>, Fe<sup>2+</sup>, Zn<sup>2+</sup> and Mn<sup>2+</sup> (0.1, 1.0 and 10.0 mM) did not affect the activity except in the case of Cu<sup>2+</sup> (10 mM). Ca<sup>2+</sup> (2.5 mM) and Mg<sup>2+</sup> (2.5 mM) in the reaction mixture caused inhibition and activation, respectively. Ca<sup>2+</sup> inhibition was partially reverted by Mg<sup>2+</sup>. The enzyme is not inhibited by products. Km and Vmax value for PGA was determined to be 0.198 ± 0.013 g.Lsup>−1</sup> and 0.0509 ± 0.0032 µmol.mLsup>−1</sup>.minsup>−1</sup> respectively. This Km value is one of the lowest reported for microbial PGases from different origins. |
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