A Water-soluble Arabinogalactan-Peptide From Wheat Endosperm

Fincher, GB; Stone, BA

doi:10.1071/bi9740117

Cited by 147 publications

(85 citation statements)

References 24 publications

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“…Of these, only endoxylanase would be expected to degrade the intact polymer. The value for the mol wt of the polymer obtained on Sepharose 4B-200 (=8 x 10a to =106) agrees well with the value obtained by Fincher and Stone (10,11) for wheat endosperm arabinoxylan (='7 x 104 to =106). The initial products of enzymolysis are of intermediate mol wt, with low mol wt products appearing only after prolonged digestion.…”

Section: Discussionsupporting

confidence: 78%

Production of Cell Wall Hydrolyzing Enzymes by Barley Aleurone Layers in Response to Gibberellic Acid

Taiz¹,

Honigman²

1976

Plant Physiol.

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The cell wails of barley (Hordeum vulgare var. Himalaya) aleurone layers undergo extensive degradation during the tissue's response to gibbereilic acid. Previous work had shown that these cell wails consist almost entirely of arabinoxylan. In this study we show that gibbereilic acid stimulates endo-fi-1,4-xylanase activity in isolated aleurone layers. In addition, gibbereilic acid enhances the activity of two glycosidases: /8-xylopyranosidase and a-arabinofuranosidase. No gibbereilic acid-stimulated ceilulase activity was detected. Germination studies showed a similar pattern of enzyme development in intact seeds.Aleurone layers of barley and other cereal grains respond to gibberellic acid by synthesizing and releasing a select group of hydrolases, including a-amylase, protease, ribonuclease, f8-1,3-glucanase, and phosphatase (14, 25). These enzymes serve to solubilize the stored food reserves of the endosperm for use by the growing embryo. Hydrolase secretion is accompanied by the nearly complete autolysis of aleurone cell cytoplastic constitutents, as well as the thick cell walls (13,16,23 aleurone layers. We also extend previous cytological studies to include scanning electron microscopy in order to monitor the physical degradation of the wall. MATERIALS AND METHODSPlant Material. Barley seeds (Hordeum vulgare L. cv. Himalaya, 1972 harvest) were either sown directly into moist Vermieulite or were surface sterilized for 25 min in 20 % Clorox, rinsed with sterile distilled H20, and sown on moist, sterile sand in 250-ml Erlenmeyer flasks. The seeds were germinated in a growth chamber at a photoperiod of 14 hr and a constant temperature of 25 C.Isolated aleurone layers were prepared from imbibed halfseeds and treated with gibberellic acid by the procedure of Chrispeels and Varner (5), with the exception that succinate buffer (20 mm, pH 5.2) was substituted for acetate buffer (6, 12).Enzyme Assays. At the end of the incubation period, the medium from the GA-treated aleurone layers was decanted into 12-ml conical centrifuge tubes. The layers were rinsed once with 3 ml of succinate buffer (20 mm, pH 5.2) containing 10 mM CaCl2, and the combined medium and washings were centrifuged at 3000g for 5 min. Extractable enzyme was prepared by grinding the aleurone layers to a paste with a small amount of sand in a mortar which had been previously rinsed with succinate-CaCl2 buffer. Five ml of the buffer were added and the homogenate was poured into centrifuge tubes and centrifuged as above. Germinating seeds were extracted in the same manner after first removing the embryos. The supernatants obtained were either used directly or were further treated by precipitation with cold ethanol as described by Taiz and Jones (23) or with 75 % ammonium sulfate. The ammonium sulfate precipitate was redissolved in 1 ml of grinding buffer and dialyzed overnight at 4 C against the same buffer before use. Although initial experiments were carried out using the ethanol procedure it was subsequently determined that precipitation with ...

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Section: Discussionsupporting

confidence: 78%

Production of Cell Wall Hydrolyzing Enzymes by Barley Aleurone Layers in Response to Gibberellic Acid

Taiz¹,

Honigman²

1976

Plant Physiol.

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“…3 -9 The extracts that are produced by these approaches typically contain approximately 60% WEAX, 30% AGP and contaminants which include glucose polymers (α-D-glucans or β-glucans) and protein. 3 -11 WEAP extracts that contain both WEAX and AGP are not appropriate for studies that aim to investigate the influence of either of the WEAP components on the properties of food products because they possess different chemical properties 12 and behave differently in bread making. 13 WEAX positively influences the properties of wheat dough and its end products 1,2,14 and confers health benefits when included in human diets.…”

Section: Introductionmentioning

confidence: 99%

A simplified method for extracting water‐extractable arabinoxylans from wheat flour

Ganguli

Turner

2008

J Sci Food Agric

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BACKGROUND: Water-extractable arabinoxylan (WEAX) is a minor constituent of wheat grain which influences the properties of wheat dough and its end products while conferring numerous health benefits. Consequently, various applications have been proposed for it in foodstuffs. Fortification of food products with pure WEAX extracts represents a simple means to evaluate its effect in these systems. However, rapid methods to isolate relatively pure WEAX are not available. This study aimed to develop a rapid, technically simple means to extract relatively pure WEAX on a small scale.

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“…Arabinoxylans (AX) are hemicelluloses built up of pentose sugars, mostly arabinose and xylose residues, and are therefore often referred to as pentosans (Izydorczyk & Biliaderis, 1995). AX consist of backbone chains of (1,4) linked-linked D-xylopyranosyl units to which -L arabinofuranosyl substituents are attached through O-2 and/or O-3 (Fincher & Stone, 1974). Some of the arabinose residues are ester linked on (O)-5 to ferulic acid (FA) (3-methoxy, 4 hydroxy cinnamic acid) (Smith & Hartley, 1983).…”

Section: Introductionmentioning

confidence: 99%

“…Some of the arabinose residues are ester linked on (O)-5 to ferulic acid (FA) (3-methoxy, 4 hydroxy cinnamic acid) (Smith & Hartley, 1983). AX are mayor dietary fiber components of many cereals like wheat, rye, corn, barley, oat, rice and sorghum (Fincher & Stone, 1974). AX are classified into water-extractable (WEAX) and water-unextractable AX (WUAX).…”

Section: Introductionmentioning

confidence: 99%