A beta-D-galactosidase from nasturtium (Tropaeolum majus L.) cotyledons. Purification, properties, and demonstration that xyloglucan is the natural substrate.
25 Mar 1988-Journal of Biological Chemistry (American Society for Biochemistry and Molecular Biology)-Vol. 263, Iss: 9, pp 4333-4337
TL;DR: It is argued that the cell-wall storage xyloglucan of the nasturtium seed is its natural substrate.
About: This article is published in Journal of Biological Chemistry.The article was published on 1988-03-25 and is currently open access. It has received 107 citations till now. The article focuses on the topics: Xyloglucan & Tropaeolum majus.
Citations
More filters
TL;DR: Immobilized β galactosidases are employed for the continuous hydrolysis of lactose from whey and milk in a number of reactors such as hollow fiber reactors, tapered column reactors, packed bed reactors, fluidized bed reactors etc.
Abstract: β Galactosidases have been obtained from microorganisms such as fungi, bacteria and yeasts; plants, animals cells, and from recombinant sources. The enzyme has two main applications; the removal of lactose from milk products for lactose intolerant people and the production of galactosylated products. In order to increase their stability, reusability, and use in continuous reactors, these enzymes have been immobilized on both organic and inorganic support via adsorption, covalent attachment, chemical aggregation, microencapsulation, and entrapment. Free and immobilized preparations of β galactosidases have been exploited in various applications such as industrial, biotechnological, medical, analytical, and in different other applications. β galactosidase is widely used in food industry to improve sweetness, solubility, flavor, and digestibility of dairy products. Immobilized β galactosidases are employed for the continuous hydrolysis of lactose from whey and milk in a number of reactors such as hollow fiber reactors, tapered column reactors, packed bed reactors, fluidized bed reactors etc.
382 citations
Cites background from "A beta-D-galactosidase from nasturt..."
...…of germinated nasturtium (Tropaeolum majus L.) seeds and it was described that the enzyme was involved in vivo hydrolysis of storage xyloglucan (Edwards et al., 1988). β Galactosidase isolated and purified from Cicer arietinum exhibited high enzyme activity and this enzyme preparation was…...
[...]
...) seeds and it was described that the enzyme was involved in vivo hydrolysis of storage xyloglucan (Edwards et al., 1988)....
[...]
TL;DR: The idea that the CWSPs are multifunctional molecules is proposed and this feature is used as evidence for the hypothesis that, during evolution, theCWSPs were involved in cycles of transference of functions which led them to become storage polysaccharides, yet preserving some of their previous primary cell wall functions.
244 citations
TL;DR: Current knowledge about plant glycoside hydrolases that participate in the degradation and reorganisation of cell wall polysaccharides in plants focussing particularly on those from Arabidopsis thaliana are summarized.
227 citations
TL;DR: It is proposed that MUM2 is involved in modifying mucilage to allow it to expand upon hydration, establishing a link between the galactosyl side-chain structure of pectin and its physical properties.
Abstract: Seed coat development in Arabidopsis thaliana involves a complex pathway where cells of the outer integument differentiate into a highly specialized cell type after fertilization. One aspect of this developmental process involves the secretion of a large amount of pectinaceous mucilage into the apoplast. When the mature seed coat is exposed to water, this mucilage expands to break the primary cell wall and encapsulate the seed. The mucilage-modified2 (mum2) mutant is characterized by a failure to extrude mucilage on hydration, although mucilage is produced as normal during development. The defect in mum2 appears to reside in the mucilage itself, as mucilage fails to expand even when the barrier of the primary cell wall is removed. We have cloned the MUM2 gene and expressed recombinant MUM2 protein, which has b-galactosidase activity. Biochemical analysis of the mum2 mucilage reveals alterations in pectins that are consistent with a defect in b-galactosidase activity, and we have demonstrated that MUM2 is localized to the cell wall. We propose that MUM2 is involved in modifying mucilage to allow it to expand upon hydration, establishing a link between the galactosyl side-chain structure of pectin and its physical properties.
166 citations
Cites background from "A beta-D-galactosidase from nasturt..."
...Furthermore, b-galactosidases isolated from nasturtium (Tropaeolum majus) cotyledons (Edwards et al., 1988) and Copaifera langsdorffii (de Alcantara et al., 1999) show activity toward the b-D-Gal-(1/2)-a-D-xylose side chains of xyloglucan but show little or no activity toward pectic b-D(1/4)-Gal....
[...]
...Furthermore, b-galactosidases isolated from nasturtium (Tropaeolum majus) cotyledons (Edwards et al., 1988) and Copaifera langsdorffii (de Alcantara et al....
[...]
TL;DR: The biotechnological tailoring of polysaccharide properties using an enzyme, as a first step in modelling or designing a poly Saccharide molecule, is described.
163 citations
References
More filters
TL;DR: All glycosyl residues (except the residue at the reducing end of an oligosaccharide, which is called a glycose residue) are glycosidically linked at C-l and this fact is assumed in the notation used, and, thus, C-\ is not mentioned.
Abstract: 1 Abbreviations and conventions used: AceA, aceric acid (3-C-carboxy-5-deoxy-L-xylose); Api, apiose; Ara, arabinose; Fuc, fucose; Gal, galactose; GalVA, galacturonic acid; Glc, glucose; GlcA, glucuronic acid; Rha, rhamnose; Xyl, xylose; PGA lyase, endo-IX-I,4polygalacturonic acid lyase; and PIIF, Proteinase Inhibitor Inducing Factor. All glycosyl residues are in the pyranoid ring form unless the furanoid form is indicated, e.g. Ara! Standard D and L notations are used when the absolute configuration of a particular glycosyl residue has been experimentally determined. When the absolute configuration has not been experiment ally determined, we omit the D or L notation, although in all cases studied the glycosyl residues Gal, Glc, Xyl, GalA, and GlcA have been found in the D configuration, and the glycosyl residues Fuc, Ara, and Rha in the L configuration. We use in this review a simplified linkage notation. All glycosyl residues (except the residue at the reducing end of an oligosaccharide, which is called a glycose residue) are glycosidically linked at C-l. This fact is assumed in the notation used, and, thus, C-\ is not mentioned. For example, a glycosyl residue designated as "terminal" (T) is glycosidically linked to another glycosyl or glycose residue only through C-J and contains no glycosyl residues linked to it. A glycosyl residue designated as 2-linked is glycosidicaUy linked to another glycosyl or glycose residue through C-J and has another glycosyl residue linked to it at 0-2. A glycosyl residue designated as 3,6-linked is glycosidically linked to another sugar through C-l and has glycosyl residues linked to it at 0-3 and 0-6; therefore, such a residue represents a branch point in a complex carbohydrate. The linkage from C l is also assumed in the notation for oligosac charides. Thus, L-Fuc � 2-D-Gal is a disaccharide in which an L-fucosyl residue is attached by an ()(-glycosidic bond from its C-l to 0-2 of a D-galactose residue. 2 Present address: Department of Bot
991 citations
TL;DR: Xyloglucan, isolated from the soluble extracellular polysaccharides of suspension-cultured sycamore (Acer pseudoplatanus) cells, was digested with an endo-beta-1,4-glucanase purified from the culture fluid of Trichoderma viride to inhibit the elongation of etiolated pea stem segments.
Abstract: Xyloglucan, isolated from the soluble extracellular polysaccharides of suspension-cultured sycamore (Acer pseudoplatanus) cells, was digested with an endo-β-1,4-glucanase purified from the culture fluid of Trichoderma viride. A nonasaccharide-rich Bio-Gel P-2 fraction of this digest inhibited 2,4-dichlorophenoxyacetic-acid-stimulated elongation of etiolated pea stem segments. The inhibitory activity of this oligosaccharide fraction exhibited a well-defined concentration optimum between 10−2 and 10−1 micrograms per milliliter. Another fraction of the same xyloglucan digest, rich in a structurally related heptasaccharide, did not, at similar concentrations, significantly inhibit the elongation.
240 citations
TL;DR: The results suggest that the changes in xyloglucan reflect the means by which auxin modifies the cell wall to cause elongation.
Abstract: Auxin promotes the liberation of a xlyoglucan polymer from the cell walls of elongating pea (Pisum sativum) stem segments. The released polymer can be isolated from the polysaccharide fraction of the water-soluble portion of tissue homogenates, thus providing as assay for this kind of metabolism. Promotion of xyloglucan metabolism by auxin begins within 15 minutes of hormone presentation. The effect increases with auxin concentration in a manner similar to the hormone effect on elongation. However, the xyloglucan effect of auxin occurs perfectly normally when elongation is completely blocked by mannitol. Metabolic inhibitors and Ca(2+), on the other hand, inhibit auxin promotion of elongation and of xyloglucan metabolism in parallel. The results suggest that the changes in xyloglucan reflect the means by which auxin modifies the cell wall to cause elongation.
166 citations
TL;DR: This chapter outlines the structures and occurrence of cell wall storage carbohydrates to give an account of current research on their metabolism and to explore their overall biological significance in the seeds which contain them.
Abstract: Publisher Summary In recent years, there has been a reawakening of interest in the physiology and biochemistry of the cell wall storage carbohydrates of seeds This chapter outlines the structures and occurrence of cell wall storage carbohydrates to give an account of current research on their metabolism and to explore their overall biological significance in the seeds which contain them Seeds are generally treated with alkali to extract polysaccharides of the “hemicellulose” type or with water to extract “gum” polysaccharides Consequently, the molecules with which this article is concerned are still widely classified as seed gums and hemicelluloses The chapter indicates the principal types of carbohydrate molecules stored in the cell walls of seeds and their distribution
159 citations
TL;DR: A highly selective pattern of wall turnover processes with an even more specific influence of auxin is indicated, suggesting that indoleacetic acid induces conversion of wall xyloglucan from insoluble to water-soluble form.
Abstract: Turnover of cell wall polysaccharides and effects of auxin thereon were examined after prelabeling polysaccharides by feeding pea (Pisum sativum var. Alaska) stem segments (14)C-glucose, then keeping the tissue 7 hours in unlabeled glucose with or without indoleacetic acid. There followed an extraction, hydrolysis, and chromatography procedure by which labeled monosaccharides and uronic acids were released and separated with consistently high recovery. Most wall polymers, including galacturonan and cellulose, did not undergo appreciable turnover. About 20% turnover of starch, which normally contaminates cell wall preparations but which was removed by a preliminary step in this procedure, occurred in 7 hours. Quantitatively, the principal wall polymer turnover process observed was a 50% decrease in galactose in the pectinase-extractable fraction, including galactose attached to a pectinase-resistant rhamnogalacturonan. Other pectinase-resistant galactan(s) did not undergo turnover. No turnover was observed in arabinans, but a doubling of radioactivity in arabinose of the pectinase-resistant, hot-acid-degradable fraction occurred in 7 hours, possibly indicating conversion of galactan into arabinan. None of the above changes was affected by indoleacetic acid, but a quantitatively minor turnover of a pectinase-degradable xyloglucan was found to be consistently promoted by indole-acetic acid. This was accompanied by a reciprocal increase in water-soluble xyloglucan, suggesting that indoleacetic acid induces conversion of wall xyloglucan from insoluble to water-soluble form. The results indicate a highly selective pattern of wall turnover processes with an even more specific influence of auxin.
155 citations