The degradation of arabinans by endo-arabinanase and arabinofuranosidases purified from Aspergillus niger

Voragen, A.G.J.; Rombouts, F.M.; Leeuwen, M.F. Searle-van; Schols, H.A.; Pilnik, W.

doi:10.1016/s0268-005x(87)80036-x

Cited by 46 publications

(30 citation statements)

References 23 publications

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“…Arabinoxylan was used as the substrate, and since, like the arabinofuranosidases, these enzymes release arabinofuranose as the only hydrolysis product [24], the reaction was carried out in 2.5 M methanol. However, under these conditions arabinose was the only hydrolysis product observed using 1H-NMR or HPAEC analysis.…”

Section: Arabinoxylan Arabinohydrolasesmentioning

confidence: 99%

“…In contrast, C~-L-arabinofuranosidases (a-L-arabinofuranoside arabinofuranohydrolase, EC 3.2.1.55) hydrolyse nonreducing C~-L-arabinofuranosyl residues from arabinofuranosecontaining substrates, releasing arabinose as the only hydrolysis product [21]. Two major types of C~-L-arabinofuranosidases can be classified according to substrate specificity, and are typified by the two enzymes isolated from Aspergillus niger [21,24]. Arabinofuranosidase A is only active against small substrates, like 4-nitrophenyl a-L-arabinofuranoside (pNPA) and short-chain arabino-oligosaccharides, while arabinofuranosidase B has similar activity on these substrates, but is also able to hydrolyse polymeric substrates like branched arabinan and arabinoxylan.…”

Section: ~ Introductionmentioning

confidence: 99%

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Stereochemical course of hydrolysis catalyzed by arabinofuranosyl hydrolases

Pitson¹,

Voragen²,

Beldman³

1996

FEBS Letters

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1~ IntroductionEnzymic hydrolysis of glycosidic linkages occurs via two m ~jor mechanisms, which result in either net retention or inversion of anomeric configuration [1]. Both hydrolytic mechmisms involve general acid catalysis and require two critical reddues (a proton donor and a nucleophile/base), which in m 9st glycosyl hydrolases are aspartate and/or glutamate resid~es 2.1.99)hydrolyse the (1 ~ 5)-C~-L-arabinofuranosyl linkages in linear arabinan in a random pattern, initially releasing arabinotriose and larger arabino-oligosaccharides as the major hydrolysis products [22]. In contrast, C~-L-arabinofuranosidases (a-L-arabinofuranoside arabinofuranohydrolase, EC 3.2.1.55) hydrolyse nonreducing C~-L-arabinofuranosyl residues from arabinofuranosecontaining substrates, releasing arabinose as the only hydrolysis product [21]. Two major types of C~-L-arabinofuranosidases can be classified according to substrate specificity, and are typified by the two enzymes isolated from Aspergillus niger [21,24]. Arabinofuranosidase A is only active against small substrates, like 4-nitrophenyl a-L-arabinofuranoside (pNPA) and short-chain arabino-oligosaccharides, while arabinofuranosidase B has similar activity on these substrates, but is also able to hydrolyse polymeric substrates like branched arabinan and arabinoxylan. Recently, other enzymes have been isolated [25,26] that are specific for arabinofuranosyl residues in arabinoxylan, and are termed arabinoxylan arabinohydrolases ((1 ~4)-[3-D-arabinoxylan arabinofuranohydrolase, EC 3.2.1.) (AXH). The AXH from Aspergillus awamori has been studied in some detail [23,25,27] and found to only cleave arabinofuranose from single-substituted xylopyranosyl residues in the xylan backbone, and has only low activity against substrates like pNPA or branched arabinan. Similar enzymes from B/fidobacterium adolescentis [26] and Trichoderma reesei (R. Kavitha, H. Gruppen and A.G.J. Voragen, unpublished) have also been recently isolated that appear to have a slightly different specificity since they are active against arabinofuranosyl groups linked to double-substituted xylopyranosyl residues, and are therefore termed AXH-d.Apart from studies with the c~-e-arabinofuranosidases from Monilinia fructigena [28,29], there has been little work examining the mechanisms by which these enzymes cleave arabinofuranosyl linkages. In this current study the stereochemical course of hydrolysis catalyzed by endo-(l ~5)-Ot-L-arabina-

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Section: Arabinoxylan Arabinohydrolasesmentioning

confidence: 99%

Section: ~ Introductionmentioning

confidence: 99%

Stereochemical course of hydrolysis catalyzed by arabinofuranosyl hydrolases

Pitson¹,

Voragen²,

Beldman³

1996

FEBS Letters

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“…The enzymic modification of these polysaccharides is technologically relevant in the processing of agricultural products like fruits, vegetables and cereals (Voragen et al, 1982(Voragen et al, , 1987.…”

Section: Introductionmentioning

confidence: 99%

The abfB gene encoding the major α-L-arabinofuranosidase of Aspergillus nidulans: nucleotide sequence, regulation and construction of a disrupted strain

Gielkens¹,

González-Candelas

Sánchez-Torres

et al. 1999

Microbiology

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“…The enzyme cleaves the arabinose side chains, allowing endo-ABN to attack the arabinan backbone. These enzymes act synergistically in degrading branched arabinan to generate L-arabinose (21).…”

mentioning

confidence: 99%

Purification and Characterization of Thermostable Endo-1,5-α- l -Arabinase from a Strain of Bacillus thermodenitrificans

Takao

Akiyama

Sakai

2002

Appl Environ Microbiol

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A strain of a thermophilic bacterium, tentatively designated Bacillus thermodenitrificans TS-3, with arabinandegrading activity was isolated. It produced an endo-arabinase (ABN) (EC 3.2.1.99) and two arabinofuranosidases (EC 3.2.1.55) extracellularly when grown at 60°C on a medium containing sugar beet arabinan. The ABN (tentatively called an ABN-TS) was purified 7,417-fold by anion-exchange, hydrophobic, size exclusion, and hydroxyapatite chromatographies. The molecular mass of ABN-TS was 35 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the isoelectric point was pH 4.5. The enzyme was observed to be more thermostable than known ABNs; it had a half-life of 4 h at 75°C. The enzyme had optimal activity at 70°C and pH 6.0. The enzyme had apparent K m values of 8.5 and 45 mg/ml and apparent V max values of 1.6 and 1.1 mmol/min/mg of protein against debranched arabinan (␣-1,5-arabinan) and arabinan, respectively. The enzyme had no pectin-releasing activity (protopectinase activity) from sugar beet protopectin, differing from an ABN (protopectinase-C) from mesophilic Bacillus subtilis IFO 3134. The pattern of degradation of debranched arabinan by ABN-TS indicated that the enzyme was an endo-acting enzyme and the main end products were arabinobiose and arabinose. The results of preliminary experiments indicated that the culture filtrate of strain TS-3 is suitable for L-arabinose production from sugar beet pulp at high temperature.Hemicelluloses compose a large fraction of plant cell walls and are a heterogeneous mixture of polysaccharides that include xylans, glucans, mannans, galactans, and arabinans. Arabinans consists of a backbone of ␣-1,5-linked L-arabinofuranosyl residues, some of which are substituted with ␣-1,2-and ␣-1,3-linked side chains of L-arabinose in the furanose conformation (1). There is some evidence to suggest that in plant cell walls arabinan is generally linked to the rhamnopyranosyl units of rhamnogalacturonan (13,14). Sakai and Sakamoto described a protopectinase (protopectinase-C [PPase-C]) from Bacillus subtilis IFO 3134 that did not catalyze polygalacturonic acid degradation (11). By endo-1,5-␣-L-arabinase (ABN) activity, PPase-C splits the ␣-1,5-L-arabinofuranoside linkage of the arabinan region in arabinogalactan, which attaches pectin to the cell wall constituents, so that PPase-C releases pectin (12). In addition to endo-ABN, ␣-L-arabinofuranosidase (␣-L-ABF) also is involved in degradation of arabinan. The enzyme cleaves the arabinose side chains, allowing endo-ABN to attack the arabinan backbone. These enzymes act synergistically in degrading branched arabinan to generate L-arabinose (21).It has been proved that L-arabinose selectively inhibits intestinal sucrase in a noncompetitive manner and reduces the glycemic response after sucrose ingestion in animals (16, 17). Based on these observations, L-arabinose can be used as a physiologically functional sugar that inhibits sucrose digestion. Effective L-arabinose production is, therefore, important in t...

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The degradation of arabinans by endo-arabinanase and arabinofuranosidases purified from Aspergillus niger

Cited by 46 publications

References 23 publications

Stereochemical course of hydrolysis catalyzed by arabinofuranosyl hydrolases

Stereochemical course of hydrolysis catalyzed by arabinofuranosyl hydrolases

The abfB gene encoding the major α-L-arabinofuranosidase of Aspergillus nidulans: nucleotide sequence, regulation and construction of a disrupted strain

Purification and Characterization of Thermostable Endo-1,5-α- l -Arabinase from a Strain of Bacillus thermodenitrificans

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