A galactomannan-hydrolysing α-galactosidase from jack fruit (Artocarpus integrifolia) seed: Affinity chromatographic purification and properties.
J Biosci
;
1987 Mar; 12(1): 61-69
Article
in English
| IMSEAR
| ID: sea-160562
ABSTRACT
An acid α-galactosidase from the seeds of the jack fruit seed (Artocarpus integrifolia) has been purified to homogeneity by affinity chromatography on a matrix formed by cross-linking the soluble α-galactose-bearing guar seed galactomannan. The 35kDa enzyme was a homotetramer of 9·5kDa subunits. Its carbohydrate part (5·5%) was composed of galactose and arabinose. The Km with p-nitrophenyl α-D-galactoside as substrate was 0·35 mM. The Ki values indicated inhibition by galactose, 1-O-methyl α-galactose and melibiose in the decreasing order. Among α-galactosides, the enzyme liberated galactose from melibiose, but not from raffinose or stachyose at its pH optimum (5·2). The guar seed galactomannan was however efficiently degalactosidated; limited enzyme treatment abolished the precipitability of the polysaccharide by the α-galactose-specific jack fruit seed lectin, and complete hydrolysis yielded insoluble polysaccharide. Though similar in sugar specificity and subunit assembly, α-galactosidase and the lectin coexisting in the jack fruit seed gave no indication of immunological identity.
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Index:
IMSEAR (South-East Asia)
Language:
English
Journal:
J Biosci
Year:
1987
Type:
Article
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