Inhibition of Emulsin by D ‐Gluconhydroximo‐1,5‐lactone and Related Compounds

European Journal of Biochemistry

et al. 1991

Self Cite

150

108

Using N-acetylglucosaminono-I ,5-lactone (1) as the reference, the inhibitory activity of its (formal) derivatives N-acetylglucosaminono-1,5-lactone oxime (2) and N-acetylglucosaminono-1,5-lactone 0-(phenylcarbamoy1)-oxime (3) was tested against P-N-acetylglucosaminidase of different origins (animal, plant, fungus). Displaying inhibition constants of 0.45 pM and 0.62 pM, for the animal and plant enzyme, respectively, the simple oxime 2 was about equally potent as the parent lactone 1, and 50-400 times more efficient than two recently described new P-N-acetylglucosaminidase inhibitors. The (phenylcarbamoy1)oxime 3 performed even better, particularly with the fungal enzyme (Ki = 40 nM), i.e. was about 350 times more potent than the lactone. In all cases competitive inhibition was observed with 4-nitrophenyl-~-N-acetylglucosaminide as the substrate. With K J K , ratios up to 3300 for 2 and 13600 for 3, the mode of action of these novel inhibitors is probably that of transition state mimicry. Suggestions are made for their use as a tool in biological research.Aldono-l,5-lactones are well known potent competitive inhibitors of glycosidases acting on substrates of the corresponding configuration [l, 21. In particular, this relates to the inhibition of P-N-acetylglucosaminidase (P-GlcNAc'ase; EC 3.2.1.30) by N-acetylglucosaminono-1,5-lactone (1; see Fig. 1) [3], although with values ranging over 0.8-660 pM [4-91 inhibitor constants display considerable variation. Such lactones are thought to adopt a conformation similar to that of a glycopyranosyl cation and to be effective as transitionstate approximates [lo] (for current views of the theory of transition state affinity and the design of enzyme inhibitors, see 11 1, 121).As glucono-l,5-lactone oxime and its phenylcarbamoyl derivative were found to be about equal or even better inhibitors of P-glucosidase than the parent lactone [ 131, investigations into the effect of the corresponding N-acetylglucosamine derivatives 2 and 3 on p-GlcNAc'ase seemed promising. In addition, to estimate the extent to which the source of the P-GlcNAc'ase might have a bearing on its susceptibility to inhibition, experiments were performed with enzymes of widely different organisms. A preliminary account of part of this work has been published [14]. Abbreviations. 4-Np-GlcNAc, 4-nitrophenyl-~-N-acetylglucosaminide; P-GlcNAc'ase, P-N-acetylglucosaminidase. MATERIALS AND METHODS SourcesEnzyme. P-N-Acetylglucosaminidase (EC 3.2.1.30).Chemical Co.), but the enzyme preparation from Mucor rouxii was obtained in this laboratory as follows. Log-phase hyphae of the fungus were cultivated [15] and the cells washed thoroughly with 20 mM Bistris pH 6.5, drained, and disrupted with glass beads (0.5 mm) in an MSK homogenizer (Braun, Melsungen) for 60 s at 4000 rpm. After removal of the beads, followed by centrifugation at 4000 x g for 5 min, and then at 54 500 x g for 45 min, the supernatant ( z 70 ml) was subjected to anion-exchange chromatography, using a column of DEAE-Sephadex A-25 (d 50 x 150 mm) and...

Section: Inhibitor Constants Of 0-n-acetylglucosaminidase Of Variousupporting

confidence: 66%

Section: Inhibitor Constants Of 0-n-acetylglucosaminidase Of Varioumentioning

confidence: 99%

N‐Acetylgucosaminono‐1,5‐lactone oxime and the corresponding (phenylcarbamoyl)oxime

Horsch

Hoesch

European Journal of Biochemistry

et al. 1991

Self Cite

150

108

“…A first lactone analogue synthesized and studied by our group is the hydroximolactone 7, prepared by oxidation of the hydroxy oximes 6, which are in equilibrium with the corresponding cyclic hydroxylamines. [57] Like the lactone, 7 has a flattened chair conformation, but is stable to basic and mildly acidic hydrolysis and ring conversion. The additional hydroxyl group allows the introduction of substituents, potentially mimicking the aglycon.…”

Section: Synthesis and Evaluation Of Lactone Analoguesmentioning

confidence: 99%

Recent Insights into Inhibition, Structure, and Mechanism of Configuration-Retaining Glycosidases

Heightman

1999

Angew. Chem. Int. Ed.

563

Not "from above", but "from the side": Configuration-retaining β-glycosidases protonate their substrate either anti or syn to the endocyclic C1-O bond as the first step in the enzymic cleavage of the glycosidic bond (see schematic drawing). Insights into the mechanism of action of glycosidases have been gained by a combination of the synthesis of inhibitors, the study of the kinetics of their inhibition, and the analysis of the crystal structures of glycosidases and glycosidase-ligand complexes.

“…In the context of our interest in glucosidase inhibitors [9] [lo], we wished to synthesize the tetrazole 1. This compound is of interest as an analogue of glucono-l,5-lactone; more precisely, it is a nonbasic diazo homologue of the amidin 6, or an analogue of nojirilactame (5), possessing an annulated ring.…”

Section: Oh Oh Ohmentioning

confidence: 99%

Synthesis of a Glucose‐Derived Tetrazole as a New β‐Glucosidase Inhibitor. A New Synthesis of 1‐Deoxynojirimycin

Ermert

1991

Helvetica Chimica Acta

Self Cite

116

The tetrazole 1 is a new 8-glucosidase inhibitor (IC50 = 8 . lo-' M, Emulsin), obtained (92%) by deprotection of 22, the product of an intramolecular cycloaddition of the azidonitrile 20. This azidonitrile was formed as an intermediate by treating the L-idu-bromide 14 or the L-idu-tosylate 19 with NaN, at 1 1 0 -1 2 5 O . It was isolated in a separate experiment. The yield of 22 from 19 reached 70%; 21 was formed as by-product (10 %). The bromide 14 (42%) and the iodide 15 (30-35%) were obtained from the nitrile 13, together with the 2,5-anhydro-~-idononitrile 16, which was formed in cu. 35-45 %. The tosylate 19 was obtained from 18 (97%). To obtain 18, the nitrile 13 was oxidized according to Swern (+ 17, 92%) and then reduced (NaBH4, CeCI,), leading to 18 and 13 (92%, 18/13 93 :7). Reduction of the tetrahydropyridotetrazole 22 with LiAIH, afforded 83% of the piperidine 23, which was deprotected to (+)-1-deoxynojirimycin hydroacetate (2. AcOH, 86 %) and further converted into the corresponding hydrochloride and into the free base 2.Introduction. -A number of glycosidase inhibitors, some of them with promising biological properties, have been isolated or designed. Among them are not only polyhydroxylated piperidines (e.g. 1-deoxynojirimycin (2) [I], nojirimycin (3) [2], and related compounds), polyhydroxylated pyrrolidines (e.g. DAB 1 [3]) and indolizidines (e.g. castanospermine (4) [4] and swainsonine [5]), but also analogues of glyconolactones (glucono-1,5-lactone [6], nojirilactame 5 [7], the amidine 6 [8], acylated hydroximolactones 7 [9], and lactone hydrazones 8 [lo]). 2 R = H 3 R = O H HO OH 7 R=OCONHPh