Multiple forms of polygalacturonase from mango (<i>Mangifera indica</i> L. cv Alphonso) fruit.

Prasanna, V. and Prabha, T. N. and Tharanathan, R. N. (2006) Multiple forms of polygalacturonase from mango (<i>Mangifera indica</i> L. cv Alphonso) fruit. Food Chemistry, 95 (1). pp. 30-36. ISSN 0308-8146

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Abstract

Polygalacturonase (PG) from mango pulp revealed three isoforms (I, II, III) upon ion exchange and gel filtration chromatography, each having an abundance of 68%, 6% and 26%, and molecular weights (Mr) 40, 51 and 45 kDa, respectively. The pH optimum for the isoforms was between 3 and 4. PG-I was stable over a wide pH range (4–7.5) unlike PG II and III, which were stable at pH 4 and 5, respectively. The optimum temperature was around 40 °C for all the three isoforms. Their apparent Km for pectic acid was in the range 0.22–0.25 mg ml⁻¹. The V_max for PG I, II and III was 5.7, 3.6 and 4.4 μmol GalA equivalent h⁻¹, respectively. Cd²⁺, Cu²⁺ and Fe²⁺ and EDTA inhibited whereas GalA, Gal, Fuc, Rha and Ara stimulated PG-I activity, in particular. The major endogenous substrates for mango PG were identified to be two rhamnogalacturonans varying in their sugar ratio. These results are discussed in the light of pectin dissolution in vivo in ripening mango.

Item Type:	Article
Additional Information:	Copyright of this article belongs to Elsevier.
Uncontrolled Keywords:	Mango; Polygalacturonase; Pectin; Endogenous substrates; Ripening; Textural softening
Subjects:	600 Technology > 08 Food technology > 24 Fruits > 06 Mango
Divisions:	Dept. of Biochemistry
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	26 Apr 2007
Last Modified:	28 Dec 2011 09:27
URI:	http://ir.cftri.res.in/id/eprint/537

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