The acid-catalyzed hydrolysis of β-d-xylofuranosides

Lönnberg, Harri; Kankaanperä, Alpo; Haapakka, K.

doi:10.1016/s0008-6215(00)83349-2

Cited by 29 publications

(3 citation statements)

References 22 publications

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“…A negative or near-zero /lg value, like a direct 180 kinetic isotope effect, is of course incompatible with a ring-opeiiing mechanism with opening of the ring being rate-determining: such a process would be govemed by a strongly positive lIg value (Lonnberg et al, 1977). The leaving gr6up of the natural substrate of the enzyme (another sitgar residue) is less electronegative than the aryl glycosides used in the present study.…”

Section: Resultsmentioning

confidence: 71%

“…Even this type of glycosidase, however, continues to provoke novel mechanistic proposals: recently Fleet (1985) and Post & Karplus (1986) have suggested that certain pyranosidases might open the pyranose ring of their substrates and first break the endocyclic C-1-0-5 bond (see Scheme 1). There is no precedent for such a process in the non-enzymic hydrolysis of pyranosides (reviewed by Sinnott, 1984), although ring-opening can be observed in some circumstances during the nonenzymic hydrolysis of furanosides (Capon & Thacker, 1967;L6nnberg & Kulonpiiai, 1977;Lonnberg et al, 1977;Lonnberg & Valtonen, 1978).…”

Section: Introductionmentioning

confidence: 99%

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Purification and mechanistic properties of an extracellular α-l-arabinofuranosidase from Monilinia fructigena

Kelly

Sinnott

Herrchen

1987

Biochemical Journal

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1. The alpha-L-arabinofuranosidase isoenzyme designated AFIII [Laborda, Archer, Fielding & Byrde (1974) J. Gen. Microbiol. 81, 151-163] was purified by sequential isoelectric focusing, hydrophobic chromatography, gel filtration and chromatofocusing. 2. The enzyme is a monomer of Mr 40,000. 3. On inactivation of the enzyme with 3H-labelled 1-alpha-L-arabinofuranosylmethyl-3-p-nitrophenyltriazene, 0.64 mol of alpha-L-arabinofuranosylmethyl residues/mol of enzyme is estimated to become attached to protein. 5. Neither first-order nor second-order rate constants for hydrolyses of aryl alpha-L-arabinofuranosides are dependent upon leaving-group acidity [beta lg(V) = -0.16 +/- 0.11; Beta lg(V/K) = -0.11 +/- 0.07; n = 7; delta pKa = 4.5] 6. Bond-breaking is nonetheless rate-limiting, as is shown by a value of 18(V) of 1.030 +/- 0.007 for the hydrolysis of p-nitrophenyl arabinoside. 7. Proton-donation to the leaving group is thus far advanced at the rate-limiting transition state for this enzyme. 8. Four alpha-L-arabinofuranosyl pyridinium salts are substrates, and an approximate beta lg(V) value of -0.9 can be estimated. 9. The absolute rate enhancement with the 4-bromoisoquinolinium salt, 2.5 X 10(9), is comparable with that observed with pyranosidases. 10. Ring-opening mechanisms can therefore be dismissed, even though they are known in the acid-catalysed hydrolysis of arabinofuranosides.

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Section: Resultsmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Purification and mechanistic properties of an extracellular α-l-arabinofuranosidase from Monilinia fructigena

Kelly

Sinnott

Herrchen

1987

Biochemical Journal

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“…( 14) All NMR spectra were recorded on a Bruker MSL-300 MHz spectrometer. (15) To the best of our knowledge, this paper reports for the first time the , 13C, and 27A1 spectra for this particular complex. Previously, the structure in the 13C chemical shift values are as follows: 1•2 (Cl) = 23.98,…”

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confidence: 85%

Exceptionally stable phenyldichlorocarbenium ion as a Friedel-Crafts intermediate: a high-field multinuclear NMR study

Racherla¹,

Daniel²,

Rajamohanan³

et al. 1989

J. Am. Chem. Soc.

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Arndt‐Eistert ‐Reaktionen in der Kohlenhydratchemie. — Synthesen biologisch wichtiger Kohlenhydrate, 15 Glycoside und Disaccharide aus Lactonen. — Lactonstrukturen und Ringdilatation

Dyong¹,

Baumeister²,

Bendlin³

1979

Chem. Ber.

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Arndr-Eistert-Reaktionenin der Kohlenhydratchemie. -Synthesen biologisch wichtiger Kohlenhydrate, 15 ') Glycoside und Disaccharide aus Lactonen. -Die Diisoamylboran-Reduktion acetylierter Aldono-y-lactone zu Lactolen und die Glycosidierung der Zucker mit Bortrifluorid-Etherat werden untersucht. Die in einer friiheren Mitteilung 5 , postulierten Voraussetzungen fur die mit der Reduktion verbundene Acetylwanderung und Ringexpansion werden bestatigt. Die Glycosidierung acetylierter Aldosen mit Bortrifluorid-Etherat scheint gegeniiber Literaturangaben 1 3 ) eine allgemein anwendbare, unter sehr milden Bedingungen verlaufende Methode zu sein. Bei Abwesenheit anderer Aglycon-Precursoren reagieren die Aldosen zu Disacchariden vom Trehalose-Typ. Ardr-Eisterr Reactions in Carbohydrate Chemispy. -Syntheses of Biologically Important Carbohydrates, 15 ') Glycosides and Disaccharides from Lactones. -On the Structure of Lactones and Their Ring EnlargementThe reduction of acetylated aldono-y-lactones with diisoamylborane and the glycosidation of the resulting sugars with boron trifluoride etherate is investigated. The prepositions for the acetyl migration and the ring expansion during the reduction, which were postulated in an earlier paper 15', are confirmed. In contrast to the literature 13), the glycosidation of acetylated aldoses with boron trifluoride etherate seems to be a generally applicable method which proceeds under very mild conditions. In the absence of further aglycone precursors the aldoses react with formation of disaccharides of the trehalose type.2,3,6-Tridesoxyaldosen wie Amicetose oder Rhodinose liegen als Antibiotika-glycone 0-gebunden (z. B. in y-Rhodomycin2.3)) oder uber eine N-Bindung (u. a. in Amicetin4-6) oder Streptolydigin '-')) als Pyranosen vor. Die freien Zucker bilden jedoch Gemische ails den anomeren Pyranosen und Furanosen: Amicetose ca. 1.2: 1 lo); Rhodinose ca. 1 : 1.7 11).In einer friiheren Mitteilung haben wir darauf hingewiesen, daR dieses Verhalten von 2,3,6-Tridesoxyhexosen zu erheblichen Schwierigkeiten bei Synthesen von Antibiotika und Antibiotikamodellen fuhren konnte, die Pyranosen vom 2,3-Didesoxy-Typ enthalten.Das Verhalten des 5,6,7-Tri-0-acetyl-2,3-didesoxy-~-u~ubin~heptono-y-lactons (1) bei der Reduktion mit Diisoamylboran und bei der Glycosidierung mit Benzylalkohol/Bortrifluorid-0 Verlag Chemie, GmbH, D-6940 Weinheim, 1979 Chemische Berichte Jahrg. 112 13 I . Dyong, L. Bnumeister und H . Bendlin Jahrg. 11 2 ~~Etherat deutete eine Moglichkeit an, die genannte Komplikation zu umgehen: 1 lieD sich fast quantitativ zu den anomeren 5,6,7-Tri-0-acetyl-2,3-didesoxy-~-~rnb~n~-heptofuranosen (2) reduzieren, die im Glycosidierungsschritt wieder fast quantitativ unter Acylwanderung yon C-5 nach C-4 und unter Ringerweiterung zu Benzyl-4,6,7-tri-0-acetyl-2,3-didesoxy-u/-~-arabino-heptopyranosid (38) reagierten '). OAc[OAc 11: R = B(C5H11)z 12: H = H 13: R = Bzl 13.

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The acid-catalyzed hydrolysis of β-d-xylofuranosides

Cited by 29 publications

References 22 publications

Purification and mechanistic properties of an extracellular α-l-arabinofuranosidase from Monilinia fructigena

Purification and mechanistic properties of an extracellular α-l-arabinofuranosidase from Monilinia fructigena

Exceptionally stable phenyldichlorocarbenium ion as a Friedel-Crafts intermediate: a high-field multinuclear NMR study

Arndt‐Eistert ‐Reaktionen in der Kohlenhydratchemie. — Synthesen biologisch wichtiger Kohlenhydrate, 15 Glycoside und Disaccharide aus Lactonen. — Lactonstrukturen und Ringdilatation

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