Seed germination studies II. Pathways for starch degradation in germinating pea seedlings

Swain, Richard R.; Dekker, Eugene E.

doi:10.1016/0926-6593(66)90093-2

Cited by 79 publications

(40 citation statements)

References 21 publications

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“…The K m value for malto-oligosaccharides decreased with an increase of the substrate's molecular weight. The α-glucosidase may preferably hydrolyse oligosaccharides liberated from starch by α-amylase to glucose without the preceding action of ß-amylase during the germination of millet seeds, although it has been suggested that α-glucosidase needs the preceding action of α-and ß-amylases to play a role during the germination of plants 35,41 .…”

Section: Limit Dextrinasementioning

confidence: 99%

“…The α-glucosidase activity had already doubled after 24 hours of germination (soaking) whereas α-amylase activity was still in a lag period 48 . Some authors 35,41 claim that α-glucosidase is part of the non-phosphorolytic pathway for the breakdown of starch by hydrolyzing the oligosaccharides produced by α-and β-amylases. However, Sun and Henson reported, that barley seed α-glucosidase can initiate the breakdown of raw starch granules and that this degradation is independent of the presence of α-amylase 40 .…”

Section: Limit Dextrinasementioning

confidence: 99%

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Optimisation of the Mashing Procedure for 100% Malted Proso Millet (Panicum miliaceum L.) as a Raw Material for Gluten-free Beverages and Beers

Zarnkow

Kessler

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et al. 2010

Journal of the Institute of Brewing

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J. Inst. Brew. 116(2), 141-150, 2010Proso millet is a gluten-free cereal and is therefore considered a suitable raw material for the manufacturing of foods and beverages for people suffering from celiac disease. The objective of this study was to develop an optimal mashing procedure for 100% proso millet malt with a specific emphasis on high amylolytic activity. Therefore, the influence of temperature and pH on the amylolytic enzyme activity during mashing was investigated. Size exclusion chromatography was used to extract different amylolytic enzyme fractions from proso millet malt. These enzymes were added into a pH-adjusted, cold water extract of proso millet malt and an isothermal mashing procedure was applied. The temperatures and pH optima for amylolytic enzyme activities were determined. The α-amylase enzyme showed highest activity at a temperature of 60°C and at pH 5.0, whereas the β-amylase activity was optimum at 40°C and pH 5.3. The limit dextrinase enzyme reached maximum activity at 50°C and pH 5.3. In the subsequent mashing regimen, the mash was separated and 40% was held for 10 min at 68°C to achieve gelatinisation. The next step in the mashing procedure was the mixture of the part mashes. The combined mash was then subjected to an infusion mashing regimen, taking the temperature optima of the various amylolytic enzymes into account. It was possible to obtain full saccharification of the wort with this mashing regimen. The analytical data obtained with the optimised proso millet mash were comparable to barley wort, which served as a control.

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Section: Limit Dextrinasementioning

confidence: 99%

Section: Limit Dextrinasementioning

confidence: 99%

Optimisation of the Mashing Procedure for 100% Malted Proso Millet (Panicum miliaceum L.) as a Raw Material for Gluten-free Beverages and Beers

Zarnkow

Kessler

Back

et al. 2010

Journal of the Institute of Brewing

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“…Germination in the dark did not inhibit the p)roduction of phosphorylase or a-amylase. Presumably, the seqtuence of production of these 2 enzymes in the dark is the same as in the light since Swain and Dekker (31) found peak phosphorylase activity at about tlle eighth day, whereas YounIg and Varner (36) reported the specific activity of a-amylase as still increasing 8 days after germination.…”

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confidence: 99%

“…In an effort to determine nmore directly and more precisely the relative importance of these enzymes in the breakdown of reserve starch granules, the cotyledons of germinating peas were examined because changes in the levels of amylase (30,35), starch ( 1), amvlase and starch (3,29), and phosphorylase (31) have already been-much studied in this tissue in different varieties and under different germination conditions. In our study we have followed the levels of starch, dextrin, free sugars, amylases, and phosphorylases of the cotyledons of the cultivar "Early Alaska", a variety of smooth seeds, during germination in the light.…”

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confidence: 99%

Enzymic Degradation of Starch Granules in the Cotyledons of Germinating Peas

1969

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Abstract. Starch, total a-and f3oamylase, and phosphorylase levels and the zymogram patterns of these 3 starch-degrading enzymes were determined in the cotyledons of smooth pea (Pisum sativum L.) during the first 15 days of germination. Starch is degraded slowly in the first 6 days; during this time, a-amylase is very low, $-amylase is present at ?a constant level while phosphorylase gradually increases and reaches a peak on the fifth day. Beginning on the sixth day there is a more rapid degradation of starch which coincides with a-amylase production. One phosphorylase band and 2 /-amylase bands are present in the zymogram of the imbibed cotyledon. An additional phosphorylase band and 1 a--amylase band appear during germination. Seeds imbibed in benzyladenine, chloramphenicol, and in cycloheximide show retarded growth and slower starch degradation and enzyme production than the controls. We conclude that a-amylase is the major enzyme involved in the initial degradation of starch into more soluble forms while phosphorylase and l3-amylase assist in the further conversion to free sugars.The enzynmic degradation of starch in plants has been attributed to phosphorylase or a-amylase in the leaves (6, 9) and to a-amylase in starch storage tissuies (30) on the basis that starch degradation usually coincides with periods of maximum activity of these enzymes. In an effort to determine nmore directly and more precisely the relative importance of these enzymes in the breakdown of reserve starch granules, the cotyledons of germinating peas were examined because changes in the levels of amylase (30,35), starch ( 1), amvlase and starch (3,29), and phosphorylase (31)

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“…We showed in previous reports ' (25,26) that a number of enzvmes required for the degradation of seed carbohydrate reserves are present in the cotvledon of the germinating pea, and at least 2 of these enzymes, an a-amylase and a phosphorylase. increase manyfold in total activity during the time period of germination.…”

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confidence: 99%

Seed Germination Studies. III. Properties of a Cell-free Amino Acid Incorporating System From Pea Cotyledons; Possible Origin of Cotyledonary α-Amylase

Swain

Dekker

1969

Plant Physiol.

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Abstract. Pea cotyledonary a-amylase increases dramaticallv both in specific activity and total activity between days 7 to 10 when germination occurs in the dark. This enzymatic activity does not seem to appear as a consequence of release or formation of an activator, removal of an inhibitor, dissociation of an inactive amylase complex, or proteolytic decomposition of a zymogen precursor. The possibility remains that the a-amylase is newly synthesized during germination. The preparation and properties of a cell-free protein-synthesizing system from germinating pea cotyledons is described; polyuridylic acid must be added for L-phenylalanine incorporation. Active microsomal preparations can be obtained from cotyledons germinated 10 days.Seed germination is frequently accompanied bv marked increases in the level of activity of certain enzymes (3,4,12,17, 23,32). It has been noted that these often dramatic increases in biocatalytic activity are not necessarily associated only with those parts of the seedling that are actively growing. Rather. the same phenomenon is also observed in the storage tissues of the endosperm or cotyledon (4, 17, 32).We showed in previous reports '(25, 26) that a number of enzvmes required for the degradation of seed carbohydrate reserves are present in the cotvledon of the germinating pea, and at least 2 of these enzymes, an a-amylase and a phosphorylase. increase manyfold in total activity during the time period of germination. Since, in many instances, the cells of plant storage organs neither grow nor divide, the question arises as to what the origin of such new enzymatic activities mlay be. Other workers dernonstrated that activation of latent enzyme occurs in the case of the ,-amylase of wheat (21,22), zymogen activation causes an increase in acid phosphatase and isocitritase activiti-es of a variety of seeds (17), whereas isocitritase (6,10). malate synthetase (10), tyramine methylpherase (12), and barley a-amvlase (5, 28) increase in activity as a result of de novo enzyme synthesis.We report here studies which show that cotvledonary a-amylase of peas most likely does not appear during germination as a consequence of the formation or release of a specific activator, the removal of an inhibitor, or the activation of a latent form (or zymogen precursor) of the enzyme. The possibility that the enzyme is newly synthesized is not eliminated.A cell-free protein-synthesizing system from the cotyledons of germinating peas has been prepared and its properties determined. A catalytically-active microsomal fraction can be prepared from cotyledons at a time during germination when the level of oa-amvlase activity is rapidlv increasilng.

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Seed germination studies II. Pathways for starch degradation in germinating pea seedlings

Cited by 79 publications

References 21 publications

Optimisation of the Mashing Procedure for 100% Malted Proso Millet (Panicum miliaceum L.) as a Raw Material for Gluten-free Beverages and Beers

Optimisation of the Mashing Procedure for 100% Malted Proso Millet (Panicum miliaceum L.) as a Raw Material for Gluten-free Beverages and Beers

Enzymic Degradation of Starch Granules in the Cotyledons of Germinating Peas

Seed Germination Studies. III. Properties of a Cell-free Amino Acid Incorporating System From Pea Cotyledons; Possible Origin of Cotyledonary α-Amylase

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