Development of Cytolytic Enzyme Activities During Germination of Different Barleys

Ballance, G. M.; Meredith, W. O. S.

doi:10.4141/cjps74-035

Cited by 14 publications

(8 citation statements)

References 5 publications

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“…1A). This is consistent with earlier reports that GA3 enhances (1--3,1l-A4)--glucanase activity in whole barley grains (3,11) and in isolated aleurone fragments (10). When Ca2`is omitted from the incubation medium, secreted (1l-3,1 l-4)--glucanase activity decreases by more than 80% (TableI).…”

Section: )supporting

confidence: 82%

“…Enzyme detected in the soluble fraction of tissue homogenates has been used to provide an indication of intracellular (1--3, 1-A)-(l-glucanase levels, although this fraction may also include enzymes trapped in the cell walls. It should also be emphasized that the substrate specificity, developmental pattern and function of (l-3,1l-)-#-glucanases (EC 3.2.1.73) examined here differ markedly from the (1-3)-#-glucanases (EC 3.2.1.39) of germinating barley (3,7,10,11,18). Furthermore, the (1l-3, 1l-4)-j3-glucanase isoenzymes require no Ca2" for activity (20, …”

Section: Preparation Ofmentioning

confidence: 99%

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Development of (1→3,1→4)-β-d-Glucan Endohydrolase Isoenzymes in Isolated Scutella and Aleurone Layers of Barley (Hordeum vulgare)

Stuart

Loi²,

Fincher³

1986

Plant Physiol.

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An immunological assay has been used to investigate the synthesis of (1-_3,1-*4)-,-glucanase (EC 3.2.1.73) isoenzymes from isolated barley aleurone layers and scutelia. Enzyme release from both tissues is enhanced by 1 micromolar gibberellic acid and 10 millimolar Ca2", although increases induced by gibberellic acid are observed only in the presence of Ca2". Isoenzyme I is synthesized predominantly in the scutellum, while isoenzyme II is synthesized exclusively in the aleurone. A third, putative isoenzyme III has been detected in significant proportions in scutellar secretions and may also be secreted from aleurone layers. Both gibberellic acid and Ca2" appear to preferentially enhance isoenzyme II secretion from the aleurone and isoenzyme III secretion from scutella. The patterns of isoenzyme secretion are suggestive of tissue-specific differences in expression of the genes which code for (1-.3,1--*4)-,-glucanase isoenzymes. Qualitatively similar results were obtained with barley cultivars harvested in Australia and North America.

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Section: )supporting

confidence: 82%

Section: Preparation Ofmentioning

confidence: 99%

Development of (1→3,1→4)-β-d-Glucan Endohydrolase Isoenzymes in Isolated Scutella and Aleurone Layers of Barley (Hordeum vulgare)

Stuart

Loi²,

Fincher³

1986

Plant Physiol.

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“…Several methodologies have been published to determine the activity of endo-acting enzymes which depolymerize polysaccharides. The most commonly used are: (i) measurement of the rate of decrease in viscosity of aqueous substrate solutions (Ballance and Meredith, 1974;Bourne and Pierce, 1970) resulting from the decrease with time of the average molecular weight of the mass distribution of the substrate; (ii) measurement of the rate of increase in reducing sugar equivalents (Chan and Baker, 1976;Denault et al, 1978) resulting from the increase with time of the molar concentration of the intermediate product; and (iii) measurement of the rate of decrease (or increase) of color in colored (or colorless) aqueous substrate solutions (McCleary and Shameer, 1987) resulting from a partial depolymerization of water-soluble (or water-insoluble), dye-labeled, and chemically modified substrates, followed by selective molecular weight precipitation (for water-soluble substrates).…”

Section: Introductionmentioning

confidence: 99%

A theoretical equation describing the time evolution of the concentration of a selected range of substrate molecular weights in depolymerization processes mediated by single‐attack mechanism endo‐enzymes

Sendra

Carbonell

1998

Biotechnol. Bioeng.

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Monitoring the time evolution of the concentration of a selected range of molecular weights of substrate, referred to as "detectable" substrate, has been used to determine endo-enzymic activities in polysaccharide depolymerizing processes. In the methodologies based on the use of dye-labeled substrates, the "detectable" substrate extends from a given molecular weight threshold downward. On the contrary, in the fluorescent probe-flow injection analysis methodology, initially developed to determine (1 --> 3)-(1 --> 4)-beta-D-glucanase activities, the "detectable" substrate extends from a given molecular weight threshold upward. Assuming that the time evolution of the molecular weight distribution of the substrate follows the most probable distribution (the enzymic attack is random and its mechanism is single attack), a theoretical equation describing the time evolution of the concentration of "detectable" substrate (from a given molecular weight threshold upward or downward) has been deduced. This equation, Wd = Wo. (1 + alphat). e-alphat, where Wd is the concentration of "detectable" substrate, Wo is the initial concentration of the substrate, t is the depolymerization time, and alpha is a parameter correlated through a hyperbola with the initial concentrations of enzyme and substrate and the Michaelis-Menten constant, Km, has been tested against different (1 --> 3)-(1 --> 4)-beta-D-glucan/(1 --> 3)-(1 --> 4)-beta-D-glucanase systems using the fluorescent probe-flow injection analysis methodology and Calcofluor as the fluorescent probe. The most important predictions of the theoretical equation, which allow accurate determination of both endo-enzymic activities and kinetic constants, have been experimentally confirmed.

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“…The cytolytic activities which change most significantly during this period are those of the endo-1,3; 1,4-13-glucanase and endo-1,3-~-glucanase enzymes (4,19). These enzymes are responsible for the degradation of the [3-glucan constituents of the endosperm cell walls.…”

Section: Introductionmentioning

confidence: 99%

Purification and amino acid sequence determination of an endo-1,3-β-glucanase from barley

Ballance

Svendsen

1988

Carlsberg Res. Commun.

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An endo-l,3-[3-glucanase was purified from malted barley by ion exchange column chromatography. The purified enzyme protein was demonstrated to be free of other proteins by SDS-polyacrylamide gel electrophoresis and had a molecular weight of 32,000. The amino acid composition of the protein was determined and the complete amino acid sequence was constructed from overlapping peptides generated by enzymatic as well as chemical cleavages. The molecule contains 306 amino acids arranged in one peptide chain. The molecular weight calculated from the sequence is 32,286. The sequence of the 1,3-[3-glucanase shows approximately 50% positional identity with two other I~-glucanases from barley and tobacco, respectively.

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Development of Cytolytic Enzyme Activities During Germination of Different Barleys

Abstract: For personal use only.

Cited by 14 publications

References 5 publications

Development of (1→3,1→4)-β-d-Glucan Endohydrolase Isoenzymes in Isolated Scutella and Aleurone Layers of Barley (Hordeum vulgare)

Development of (1→3,1→4)-β-d-Glucan Endohydrolase Isoenzymes in Isolated Scutella and Aleurone Layers of Barley (Hordeum vulgare)

A theoretical equation describing the time evolution of the concentration of a selected range of substrate molecular weights in depolymerization processes mediated by single‐attack mechanism endo‐enzymes

Purification and amino acid sequence determination of an endo-1,3-β-glucanase from barley

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