Glykosidasen

Wallenfels, Kurt; Diekmann, H.

doi:10.1007/978-3-662-38358-2_28

Cited by 3 publications

(3 citation statements)

References 202 publications

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“…We obtained arginine as the Cterminal amino acid of carboxymethylated fragments A and B. Wallenfels & Golker (1966) have reported that ,B-galactosidase has both lysine and arginine as C-terminal amino acids, although Korenman et al (1966) and Brown et al (1966) have only identified lysine as the C-terminal residue.…”

Section: Discussionmentioning

confidence: 98%

Restoration of β-galactosidase to Escherichia coli M15. Complementation studies

Marinkovic

1977

Biochemical Journal

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Carboxymethylated beta-galactosidase from Escherichia coli was dissociated at 100 degrees C to form carboxymethylated fragments A and B. The mol.wts. of carboxymethylated fragments A and B were determined by gel filtration to be 64300 and 22400 respectively. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of carboxymethylated fragments A and B that had been pretreated with 2-mercaptoethanol and sodium dodecyl sulphate yielded mol.wts. of 64000 and 22100 respectively. Carboxymethylated fragments A and B had arginine as their C-terminal amino acid. When a crude extract of E. coli M15 was filtered through a column of Sepharose 6B, it was found that carboxymethylated fragment B could restore beta-galactosidase activity when added to fractions having mol.wts. estimated to be 123000, 262000 and 506000. These fractions are referred to as ;complementable fractions'. Similarly, it was found that carboxymethylated fragment A could restore enzyme activity to tractions having mol.wts. estimated to be 63000, 253000 and 506000. Estimates of the molecular weights of the beta-galactosidase activity obtained by restoration with carboxymethylated fragments A and B were made by filtering the active enzyme through another column of Sepharose 6B. The enzyme obtained by complementation with carboxymethylated fragment B, i.e. the complemented enzyme, had mol.wt. 525000, and that obtained with carboxymethylated fragment A had mol.wts. of 525000, 646000 and 2000000. The latter finding suggests that multiple forms of complemented beta-galactosidase can exist.

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Section: Discussionmentioning

confidence: 98%

Restoration of β-galactosidase to Escherichia coli M15. Complementation studies

Marinkovic

1977

Biochemical Journal

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“…Based on the useful analogy made by Wallenfels that the dicyanomethylene group (C(CN) 2 ) and the carbonyl oxygen atom exert similar inductive and resonance effects, our approach to improve the solubility properties of aramids has been to replace the amide groups (−NHCO) with enaminonitrile groups (−NHCC(CN) 2 ) in the polymer backbone. The latter group is expected to undergo resonance interactions similar to those of the amide bond in aramids, and in the absence of substituents on the phenyl ring or N-substitution, the rigidity of the polymer backbone for poly(enamino nitriles) is expected to be retained.…”

Section: Introductionmentioning

confidence: 99%

Regularly Alternating Copoly(amide−enaminonitriles)

Moore

Kaur

1997

Macromolecules

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Regularly alternating copolymers of aromatic amide and enaminonitrile groups were synthesized by solution polycondensation of diamines containing preformed amide or enaminonitrile groups with m- or p-bis(1-chloro-2,2-dicyanovinyl)benzene or aromatic diacid chlorides, respectively. Most of the copolymers were high molecular weight materials ([η]DMF = 1.0−3.1). The copolymers were soluble in proton-accepting solvents and showed high glass transition temperatures in the range 262−320 °C. The enaminonitrile groups underwent curing between 300 and 350 °C, as do homopoly(enaminonitriles). The thermal stability (air and nitrogen) of the copolymers was good to excellent. In general, the predominantly para-substituted copolymers showed lower thermal stability than the corresponding homopoly(enaminonitriles) and Kevlar, while higher thermal stability was exhibited by the meta-substituted copolymers when compared to Nomex.

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“…In this study, we report our findings on the characterization of the amide-like character of enaminonitriles to evaluate its potential as a peptidomimic. The enaminonitrile group was first described by Wallenfel who suggested that the C(CN) 2 group is inductively equivalent to an oxygen atom. Moore et al developed synthetic approaches to make high molecular weight poly(enaminononitriles) (PEANs) where the oxygen atom of the amide bond was replaced with the C(CN) 2 moiety to give the enaminonitrile group (Chart ) .…”

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confidence: 99%

Solvent Effects on Barrier to Rotation of Enaminonitriles Using Inversion Transfer ¹H NMR Spectroscopy and FTIR Spectroscopy

et al. 2002

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The barrier to rotation and hydrogen bonding interactions of 2,2-dicyano-1-(N,N'-dimethylamino)vinylbenzene (1) were studied in a range of solvents. The barrier to rotation of 1 in chloroform was 14.8 kcal/mol and increased by 1.7 kcal/mol in a protic solvent, trifluoroethanol. FTIR studies showed a shift in the cyano stretch of 1 to a higher wavenumber in trifluoroethanol, which is consistent with 1 participating in a hydrogen bonding interaction at the vinyl carbon (C(v)) of the enaminonitrile group.

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Glykosidasen

Cited by 3 publications

References 202 publications

Restoration of β-galactosidase to Escherichia coli M15. Complementation studies

Restoration of β-galactosidase to Escherichia coli M15. Complementation studies

Regularly Alternating Copoly(amide−enaminonitriles)

Solvent Effects on Barrier to Rotation of Enaminonitriles Using Inversion Transfer ¹H NMR Spectroscopy and FTIR Spectroscopy

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Glykosidasen

Cited by 3 publications

References 202 publications

Restoration of β-galactosidase to Escherichia coli M15. Complementation studies

Restoration of β-galactosidase to Escherichia coli M15. Complementation studies

Regularly Alternating Copoly(amide−enaminonitriles)

Solvent Effects on Barrier to Rotation of Enaminonitriles Using Inversion Transfer 1H NMR Spectroscopy and FTIR Spectroscopy

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Solvent Effects on Barrier to Rotation of Enaminonitriles Using Inversion Transfer ¹H NMR Spectroscopy and FTIR Spectroscopy