�ber den Einflu� des Molek�lbaus auf das Vorkommen von kristallinen F�ssigkeiten

Weygand, C.; Gabler, R.

doi:10.1007/bf01488832

Cited by 19 publications

(12 citation statements)

References 4 publications

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“…Acid (20). At 95", 4(5),4(5)-bis(trifluoromethyl)-2,2'-bi-lHimidazole [26] 4'(5')-dicurhoxylate (21). A mixture of 20 (0.3 g, 0.81 mmol), EtOH (20 ml), and conc.…”

Section: (5)4'(5')-bis(uminomethyl)-22'-bi-ih-imiduzole Bis(hydrocmentioning

confidence: 99%

Synthesis and Properties of Macrobicyclic Cryptates Incorporating Five‐ and Six‐Membered Biheteroaryl Units

Lehn¹,

Vains²

1992

Helvetica Chimica Acta

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The socium cryptates of the macrobicyclic ligands 1–6 have been synthesized by direct macrobicyclisation or by stepwise procedures. They incorporate 2,2′‐bithiazole, 2,2′‐biimidazole, 2.2′‐bipyrimidine as well as 2,2′‐bipyridine units. Treatment of the sodium complexes with europium(III) chloride gave the corresponding EuIII cryptates. The structural and spectral properties of these compounds are described. The EuIII complexes present characteristic 1H‐NMR chemical‐shift features. Their luminescence properties are described.

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“…Acid (20). At 95", 4(5),4(5)-bis(trifluoromethyl)-2,2'-bi-lHimidazole [26] 4'(5')-dicurhoxylate (21). A mixture of 20 (0.3 g, 0.81 mmol), EtOH (20 ml), and conc.…”

Section: (5)4'(5')-bis(uminomethyl)-22'-bi-ih-imiduzole Bis(hydrocmentioning

confidence: 99%

Synthesis and Properties of Macrobicyclic Cryptates Incorporating Five‐ and Six‐Membered Biheteroaryl Units

Lehn¹,

Vains²

1992

Helvetica Chimica Acta

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“…6-Diazo-5-oxo-~-norleucine was synthesized as reported previously [13] by the method described by Weygand and Reiher [20,21].…”

Section: Synthesis Of 6-diazo-5-oxo-~-norleucinementioning

confidence: 99%

Latent Active Site in Rat-Kidney gamma-Glutamyl Transpeptidase. The Refolding Process of the Large Subunit and Characterization of the Renatured Enzyme

1980

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Rat kidney y-glutamyl transpeptidase (EC 2.3.2.2) is composed of two non-identical subunits (the large and small subunits). In the native state of this enzyme, the active site resides on the small subunit. The present investigation has been performed to confirm and extend in further detail the previously described finding that the large subunit isolated from the native dimeric enzyme is also catalytically active [S. Horiuchi, M. Inoue and Y. Morino (1978) Biochem. Biophys. Res. Commun. 80,873 -8781. A pure preparation of y-glutamyl transpeptidase which had been completely inactivated by affinity labeling with 6-diazo-5-oxo-~-norleucine was dissociated into the small subunit and the large subunit under denaturating conditions. Upon renaturation, only the large subunit restored the enzymic activity.Sephadex G-200 column chromatography of the renatured preparation of the large subunit revealed the presence both of enzymically inactive aggregate forms and the enzymically active species. The enzymically active molecules of the renatured large subunit behaved as particles having a molecular weight of 48000 2 2000. This indicates that the enzymically active species of the large subunit has a monomeric structure.Under the present experimental conditions, the restoration of enzymic activity of the large subunit was optimal at a protein concentration of approximately 150 pg/ml and seemed to require the presence of glutathione or its S-methyl derivative as a substrate ligand.The restoration of the enzymic activity of the large subunit was accompanied by a conformational change as judged by both circular dichroic and immunochemical properties.Some kinetic properties of the reaction with y-glutamyl-p-nitroanilide and the affinity label, 6-diazo-5-oxo-~-norleucine were essentially identical between the renatured large subunit and the native oligomeric enzyme. y-Glutamyl transpeptidase catalyzes the transfer reaction of a y-glutamyl moiety of glutathione or S-substituted glutathione derivatives to acceptors such as amino acids and peptides [1,2]. Many proposals have been made on the possible participation of this enzyme in physiological functions, including ammoniagenesis in metabolic acidosis [3,4], mercapturate biosynthesis [5,6], amino acid and peptide transport [7 -91 and so forth. Rat kidney y-glutamyl transpeptidase consists of two non-identical subunits (the large and small subunit) [lo-121. The small subunit has been shown to have an active site which is labeled by 6-diazo-5-oxo-~-norleucine, an affinity label for this enzyme [13,14], suggesting that the small subunit is a catalytic component of the enzyme. However, little has been known about the functional Enzyme. y-Glutamyl transpeptidase (EC 2.3.2.2) aspect of the large subunit except that this subunit may be mainly involved in anchoring this membranous enzyme into the renal brush border membrane [ l l , 12,151.When we studied subunit-subunit interaction of y-glutamyl transpeptidase to gain an insight into the possible functional role of the large subunit, a re...

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“…Alanine. These derivatives were prepared from their respective amino acids according to the method of Weygand and Leising [24] and extracted and purified according to the procedure of Fones and Lee [25]. The derivatives were shown to be homogeneous and free of unreacted amino acids by thin-layer chromatography on silica plates using butan-l-ol/acetic acid/ water (4/1/1, by vol.)…”

Section: N-trifuoroacetyl Derivatives Of Glycine and P-mentioning

confidence: 99%

The Synthesis of Several 8-Substituted Derivatives of Adenosine 5'-Monophosphate to Study the Effect of the Nature of the Spacer Arm in Affinity Chromatography

Lowe

1977

Eur J Biochem

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Reaction of adenosine 5'-monophosphate (Ado-5'-P) with bromine at pH 4.0 yielded 8-bromoadenosine 5'-monophosphate and following reaction with several @,coo-diaminoalkanes gave the corresponding 8-(co-aminoalkyl)-Ado-5'-P derivatives. Condensation of these analogues with N-trifluoroacetyl-glycine or /I-alanine in the presence of a water-soluble carbodiimide generated several 8-substituted derivatives. These analogues : I OH comprised an %substituted Ado-5'-P ligand to which a spacer molecule of similar length but differing hydrophobicity was attached. The derivatives were purified, characterised and attached to CNBractivated Sepharose. The chromatographic behaviour of the resulting adsorbents was investigated in terms of their ability to bind both lactate and alanine dehydrogenase. The enzymes bound tighter to the more hydrophobic derivatives with the strength of the interaction decreasing with increasing hydrophilicity. The effect of the introduction of a single hydroxyl group in the spacer arm was also studied with several enzymes known to exhibit anomalous behaviour on affinity chromatography. In each case binding was weaker to the derivative bearing the more hydrophilic spacer arm. In free solution, (Ado-5'-P)-8-NH CH2CH2CH2CH2CH2CH2NH2 and (Ado-5'-P)-S-NH CH2-CH CH2NH CO CHzNH2 were competitive with NADH for rabbit muscle lactate dehydrogenase, OHwith Ki values of 2.0 and 1.8 mM respectively. These data suggest a difference in accessibility of the hydrophobic and hydrophilic derivatives when attached to Sepharose rather than a fundamental difference in affinity. This suggestion is supported by the fact that there is no obvious correlation between the Ki values in free solution of a series of 8-(w-aminoalkyl)-Ado-5'-P derivatives of increasing chain length, and hence hydrophobicity, and their chromatographic behaviour when immobilised. The data suggest that the hydrophobicity/hydrophilicity of the spacer arm determine the accessibility of the immobilised ligand to interaction with the complementary enzyme.

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�ber den Einflu� des Molek�lbaus auf das Vorkommen von kristallinen F�ssigkeiten

Cited by 19 publications

References 4 publications

Synthesis and Properties of Macrobicyclic Cryptates Incorporating Five‐ and Six‐Membered Biheteroaryl Units

Synthesis and Properties of Macrobicyclic Cryptates Incorporating Five‐ and Six‐Membered Biheteroaryl Units

Latent Active Site in Rat-Kidney gamma-Glutamyl Transpeptidase. The Refolding Process of the Large Subunit and Characterization of the Renatured Enzyme

The Synthesis of Several 8-Substituted Derivatives of Adenosine 5'-Monophosphate to Study the Effect of the Nature of the Spacer Arm in Affinity Chromatography

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