The Limit-Dextrinase Activity of Barley Malts

Kneen, Eric; Spoerl, Joan M.

doi:10.1080/00960845.1948.12006238

Cited by 10 publications

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References 6 publications

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“…The present results show that this enzyme occurs in germinated barley; a similar enzyme is also present in sweet corn" and in broad beans. [4][5][6][7][8][9][10][11][12][13][14] The description of the absolute specificity of a polysaccharide debranching enzyme is not easy. Although all the inter-chain [J. Inst.…”

Section: Discussionmentioning

confidence: 99%

STUDIES ON CARBOHYDRATE-METABOLIZING ENZYMES Part XXV. THE DEBRANCHING ENZYME SYSTEM IN GERMINATED BARLEY

Manners¹,

Rowe²

1971

Journal of the Institute of Brewing

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Extracts of germinated barley contain two debranching enzymes which have been separated from each other, and from α‐amylase, by continuous electrophoresis followed by gel filtration. Amylopectin 6‐glucanohydrolase hydrolyses the outer‐most inter‐chain linkages in amylopectin but has no action on glycogen or on α‐limit dextrins. Limit dextrinase has no action on amylopectin, but readily hydrolyses α‐limit dextrins; it differs fron amylopectin 6‐glucanohydrolase in having a relatively lower activity at pH 4, pH 7 or 60° C, and is selectively activated by chloride ions.

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Section: Discussionmentioning

confidence: 99%

STUDIES ON CARBOHYDRATE-METABOLIZING ENZYMES Part XXV. THE DEBRANCHING ENZYME SYSTEM IN GERMINATED BARLEY

Manners¹,

Rowe²

1971

Journal of the Institute of Brewing

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Enzymes of Starch Degradation and Synthesis

Bernfeld¹

1951

Advances in Enzymology - And Related Areas of Molecular Biology

328

172

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Studies on Debranching Enzymes. Part I the Limit Dextrinase Activity of Extracts of Certain Higher Plants and Commercial Malts

Manners¹,

Yellowlees²

1973

Journal of the Institute of Brewing

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Using pullulan as the substrate, the limit dextrinase activity of protein extracts from higher plants and from commercial malts has been measured. Extracts of ungerminated barley, rye, maize and wheat show low levels of activity which increase markedly on germination.By contrast, extracts of ungerminated oats have a high level of activity which does not increase during germination. Gibberellic acid has a significant effect on the rate of develop* ment of limit dextrinase activity in barley. Commercial samples of malt show varying amounts of limit dextrinase activity which does not correlate with the diastatic power. For comparative purposes, the a-amylase and maltotriase activities of all the protein extracts have also been measured.Key words: barley, cereal, dextrin, enzyme, gibbereUin, hydrolysis, malt, malting, starch. IntroductionThe enzyme limit dextrinase catalyses the hydrolysis of a-(l-»-6)-D-glucosidic inter chain linkages in a-dextrins which result from the a-amylolytic degradation of amylopectin. Limit dextrinase may also hydrolyse similar linkages in amylopectin-type polysaccharides, but in all cases, there is no action on the major oc-(l-*4)-D-glucosidic linkages.4'20 Since Pazur30 has stated "it is questionable that limit dextrinase is a distinct enzyme entity," and others18 have described evidence which was considered to be "added proof of the non-existence of a separate limit dextrinase," we now wish to review the present status of this enzyme, and to describe a survey of its distribution in certain higher plants and barley malts. This discussion will be confined to enzymes originating from higher plants; it has been known for many years15 that fungal amylase preparations contain an additional enzyme which releases glucose (fermentable sugar) from a-dextrins (non-fermentable carbo hydrate) but this activity is now known to be due to an a-glucosidase3 which may hydrolyse both ec-(l-»4)-and 4)-glucosidic linkages. It might be hypothesized then that the action of malt limit dextrinase could be primarily one of breaking the (l-M5)-glucosidic linkages." The correctness of this hypothesis has been proved by our experimental results.24-28 The statements by Lee & Whelan18 that "limit dextrinase is a name of ancient currency in the brewing industry that describes an enzyme (s) prepara tion y...

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The Limit-Dextrinase Activity of Barley Malts

Cited by 10 publications

References 6 publications

STUDIES ON CARBOHYDRATE-METABOLIZING ENZYMES Part XXV. THE DEBRANCHING ENZYME SYSTEM IN GERMINATED BARLEY

STUDIES ON CARBOHYDRATE-METABOLIZING ENZYMES Part XXV. THE DEBRANCHING ENZYME SYSTEM IN GERMINATED BARLEY

Enzymes of Starch Degradation and Synthesis

Studies on Debranching Enzymes. Part I the Limit Dextrinase Activity of Extracts of Certain Higher Plants and Commercial Malts

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