Showing papers on "Xylanase published in 1977"

Xylanase from Trichoderma pseudokoningii: Purification, Characterization, and Effects on Isolated Plant Cell Walls

Abstract: BAKER, C. J., C. H. WHALEN, and D. F. BATEMAN. 1977. Xylanase from Trichoderma pseudokoningii: purification, characterization, and effects on isolated plant cell walls. Phytopathology 67:1250-1258. Trichoderma pseudokoningii produced an extracellular xylose from /3-1,4 xylan. It did not hydrolyze arabinan endo-31,4 xylanase when grown in shake culture at 25 C on a (araban), carboxymethylcellulose, /3-1,4 galactan, mannan, mineral salts medium containing 0.1% /3-1,4 xylan as the sole glucomannan, sodium polypectate, or polygalacturonic acid. carbon source. Enzyme activity was determined by It had a pH optimum of 5.0, a pI of about 9.6, a molecular measuring the release of reducing groups from xylan or 0weight of 15,000 to 22,000, and was stable in 50 mM sodium hydroxyethyl xylan. Dialyzed culture filtrates from 4-dayacetate buffer (pH 5.0) at -20 C for up to 9 mo. The purified old cultures were subjected to ion exchange chromatography endo-P3-1,4 xylanase readily solubilized carbohydrate on CM-Sephadex (C-25) in 20 mM sodium acetate buffer containing xylose and arabinose from isolated cell walls of 5(pH 5.0); xylanase was eluted with a linear salt gradient (0day-old corn seedlings, and solubilized, to a lesser extent, 150 mM NaCl in buffer). Fractions containing the enzyme carbohydrate containing primarily xylose from isolated cell were dialyzed, lyophilized, dissolved in water, and subjected walls from hypocotyls of 7-day-old bean seedlings. This to gel filtration on Bio-Gel P-10 equilibrated with 50 mM enzyme should be valuable in evaluating the role of xylanase sodium acetate buffer (pH 5.0) containing 100 mM NaCl. in cell wall hydrolysis by pathogens and in helping to further This two-step procedure yielded a 28-fold purification of the elucidate plant cell wall structure. xylanase. The purified enzyme released only oligomers of Additional key words: cell wall degradation, xylan. The D-xylans are polysaccharides found in the pseudokoningii, a nonpathogen, would be a good source hemicellulosic fraction of higher plant cell walls. These for this enzyme. Here we report the purification and polymers consist of a/3-1,4-linked D-xylopyranose chain characterization of an endo-/3-1,4 xylanase (EC 3.2.1.8) which commonly has side branches of a-l,3-linked Lproduced by T.pseudokoningii and present evidence that arabinofuranose and a-1,2-linked D-glucuronopyranose cell wall sugars are released from isolated corn (Zea mays (or its 4-0-methyl ether). The number and kinds of branch L.) and bean (Phaseolus vulgaris L.) cell walls by this residues are characteristic for different plant groups. xylanase. Preliminary reports of these studies have been Some xylans are acetylated at carbons 2 and 3 of the made (2, 4). xylopyranose residues (35). The D-xylans are found in almost all land plants (31) MATERIALS AND METHODS and they are the principal components of the primary cell walls of monocots (7). Since a number of microorganisms Commercial xylan (larchwood) was obtained from pathogenic to such plants are known to produce ICN Pharmaceuticals, Inc. Cleveland, OH 44128. xylanases (5, 6, 10, 25, 30, 33), it is of interest to know Cytochrome C from horse heart, horseradish peroxidase, whether or not the degradation of these polysaccharides ribonuclease A, and a-chymotrypsinogen A were plays a role in pathogenesis. The degradation of the obtained from Sigma Chemical Co., St. Louis, MO xylopyranosyl chain by microorganisms can be 63178. Ampholines for isoelectric focusing were accomplished through random hydrolytic cleavage of the purchased from LKB Instruments, Inc., Rockville, MD /3-1,4 glycosidic bonds by xylanases (8, 9, 11, 12, 17, 34). 20852. Carboxymethylcellulose (Type 7 MP) was To study the effects of these enzymes on plant cell walls obtained from Hercules Inc., Wilmington, DE 19899. and to evaluate their possible role in pathogenesis, pure Polygalacturonic acid was purchased from the Sunkist enzyme preparations are needed. Such preparations also Growers, Inc., Ontario, CA 91764. Mannan was would serve as powerful tools in the further elucidation of purchased from K & K Laboratories, Plainview, NY the plant cell wall structure. A survey of several 11803, and araban was obtained from Koch-Light microorganisms that produce xylanases that could be Laboratories, Ltd., Colnbrook, U.K. Beta-l,4 galactan purified readily indicated that Trichoderma was purified from Lupinus albus L. by the procedure of Jones and Tanaka (13). Glucomannan was prepared from Copyright © 1977 The American Phytopathological Society, 3340 the commercial xylan as described below. Xylan was Pilot Knob Road, St. Paul, MN 55121. All rights reserved, further purified from the commercial larchwood xylan

Gibberellic-acid-induced synthesis and release of cell-wall-degrading endoxylanase by isolated aleurone layers of barley.

Abstract: When aleurone layers of barley (Hordeum vulgare L.) are incubated with gibberellic acid (GA3) xylose and arabinose—both as free sugars and bound to larger molecules—are released into the medium. Release begins 10–12h after the start of incubation and continues for at least 60h. At the same time there is a GA3-induced breakdown of the cell wall resulting in a loss of 2/3 of the cell-wall pentose during 60h of incubation. GA3 causes the appearance in the medium of an enzyme (or enzymes) which hydrolyze larchwood xylan and aleurone-layer arabinoxylan. Release of the enzyme(s) into the medium begins 28–32h after the start of incubation. Enzyme activity does not accumulate to any large extent in the tissue prior to release into the medium, and is present in very low levels only in the absence of GA3. Xylanase activity is associated with a protein (or proteins) with a molecular weight of 29,000. The hydrolysis of the xylans is largely caused by endoxylanase activity, indicating the importance of endoglycosidases in the GA3-induced breakdown of the aleurone cell wall.

Cellulase and Xylanase Production by Yeasts of the Genus Trichosporon

Abstract: Summary The optimum conditions for cellulase production in culture filtrates by Trichosporon cutaneum and T. pullulans were determined. With ball-milled filter paper as a test substrate maximum activity was detected 4 to 7 days after transfer from glucose to cellulose (ball-milled filter paper) as growth substrate. Comparison of the yeast filtrates with those from the moulds Trichoderma viride and Myrothecium verrucaria showed that the total activity of one strain of T. pullulans was comparable to that of the moulds with ball-milled filter paper as assay substrate. Activities were always lower when α-cellulose or dewaxed cotton were used as assay substrates. The main products of cellulose degradation were cellobiose and glucose, although the ratio of these products clearly differentiated between culture filtrates of the species examined. Xylanase activity was present in all the culture filtrates examined. Polyacrylamide gel electrophoresis of active filtrates produced strain-specific patterns of three to five stained bands with similar mobilities but an inactive filtrate lacked one band common to all the other filtrates.

Process for the production of xylose by enzymatic hydrolysis of xylan

Abstract: A process for the production of xylose by enzymatic hydrolysis of xylan wherein an aqueous solution containing xylan is treated with a carrier having bonded thereto xylanase enzyme and a carrier having bonded thereto β-xylosidase and, optionally, uronic acid-splitting enzyme.

[Fractionation and purification of endo-1,4-beta-xylanases and exo-1,4-beta-xylosidases of Aspergillus niger].

Abstract: Two endo-1,4-beta-zylanases (m. w. 24,000 and 41,000) and six exo-1,4-beta-xylosidases, differing in their molecular weights and isoelectric points, were found in a xylanase preparation from Aspergillus niger, using different methods of fractionation. An electrophoretically homogeneous exo-1,4-beta-xylosidase (m. w. 30,000) purified 120-fold, with pI 4.6, having optimal effect on methyl-beta-D-xyloside at pH 3.0 was obtained. Exo-1,4-beta-xylosidase splits off xylose from the ends of the xylan chains at xylotriose, xylobiose and methyl-beta-D-xyloside and is characterized by a high transglycosilase activity. An electrophoretically homogeneous endo-1,4-beta-xylanase (m. w. 24,000) purified 250-fold, with pI 4.2 and optimal effect on carboxymethylxylan at pH 4.2 was isolated. Endo-1,4-beta-xylanase splits arabinoglucuronoxylan to form xylooligosaccharides; however, it does not hydrolyze xylobiose.