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41.
Dr. Karin Mannerstedt Dr. Narendra Kumar Mishra Dr. Ebbe Engholm Dr. Morten Lundh Dr. Charlotte S. Madsen Dr. Philip J. Pedersen Dr. Priska Le-Huu Dr. Søren L. Pedersen Dr. Nina Buch-Månson Dr. Björn Borgström Dr. Thomas Brimert Dr. Lisbeth N. Fink Dr. Keld Fosgerau Prof. Niels Vrang Prof. Knud J. Jensen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(9):3166-3176
A glucose responsive insulin (GRI) that responds to changes in blood glucose concentrations has remained an elusive goal. Here we describe the development of glucose cleavable linkers based on hydrazone and thiazolidine structures. We developed linkers with low levels of spontaneous hydrolysis but increased level of hydrolysis with rising concentrations of glucose, which demonstrated their glucose responsiveness in vitro. Lipidated hydrazones and thiazolidines were conjugated to the LysB29 side-chain of HI by pH-controlled acylations providing GRIs with glucose responsiveness confirmed in vitro for thiazolidines. Clamp studies showed increased glucose infusion at hyperglycemic conditions for one GRI indicative of a true glucose response. The glucose responsive cleavable linker in these GRIs allow changes in glucose levels to drive the release of active insulin from a circulating depot. We have demonstrated an unprecedented, chemically responsive linker concept for biopharmaceuticals. 相似文献
42.
Siebert HC Born K André S Frank M Kaltner H von der Lieth CW Heck AJ Jiménez-Barbero J Kopitz J Gabius HJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,12(2):388-402
The branched pentasaccharide chain of ganglioside GM1 is a prominent cell surface ligand, for example, for cholera toxin or tumor growth-regulatory homodimeric galectins. This activity profile via protein recognition prompted us to examine the binding properties of peptides with this specificity. Our study provides insights into the mechanism of molecular interaction of this thus far unexplored size limit of the protein part. We used three pentadecapeptides in a combined approach of mass spectrometry, NMR spectroscopy and molecular modelling to analyze the ligand binding in solution. Availability of charged and hydrophobic functionalities affected the intramolecular flexibility of the peptides differently. Backfolding led to restrictions in two cases; the flexibility was not reduced significantly by association of the ligand in its energetically privileged conformations. Major contributions to the interaction energy arise from the sialic acid moiety contacting Arg/Lys residues and the N-terminal charge. Considerable involvement of stacking between the monovalent ligand and aromatic rings could not be detected. This carbohydrate binding strategy is similar to how an adenoviral fiber knob targets sialylated glycans. Rational manipulation for an affinity enhancement can now be directed to reduce the flexibility, exploit the potential for stacking and acquire the cross-linking capacity of the natural lectins by peptide attachment to a suitable scaffold. 相似文献
43.
A discontinous gel system is described that is composed of the dissolvable, disulphide-containing acrylamide gel developed by Hansen and the acetic acid-urea gel as introduced by Panyim and Chalkley. A cleavable SDS gel is used for the identification and an initial separation of proteins according to molecular weight; it is then solubilized by tris-mercaptoethanol and layered on the acidic gel, where it functions as a stacking gel with a pronounced concentrating capacity. The final resolution obtained by this technique permits the identification of single protein species according to the degree of enzymatic modification (acetylation and phosphorylation). Side reactions of the disulphide gel matrix with thiol proteins are discussed and other possible application are considered. 相似文献
44.
N. Ahmad C. Nanjundayya W. G. Chace M. A. Ssobolew M. M. Tschilikin A. T. Iwanowa F. Kalmanowitsch A. Kolotyrewa C. F. Cross E. J. Bevan A. Eavenson J. W. Creely J. H. Skinkle O. Viertel A. J. Hall W. N. Udalskaja D. A. Clibbens A. H. Little Karin Schulze S. M. Edelstein E. Lindemann F. Schütz W. Klauditz P. Winterfeld F. H. Guernsay L. T. Howells F. Schroeder R. Finlay G. Hasse Niederhauser H. Ris R. D. Nutting W. Lesnianski F. Fabrowicz und Coch 《Fresenius' Journal of Analytical Chemistry》1938,115(1-2):51-57
Ohne Zusammenfassung 相似文献
45.
Nienhaus K Nar H Heilker R Wiedenmann J Nienhaus GU 《Journal of the American Chemical Society》2008,130(38):12578-12579
An important class of red fluorescent proteins (RFPs) feature a 2-iminomethyl-5-(4-hydroxybenzylidene)imidazolinone chromophore. Among these proteins, eqFP611 has the chromophore in a coplanar trans orientation, whereas the cis isomer is preferred by other RFPs such as DsRed and its variants. In the photoactivatable protein asFP595, the chromophore can even be switched from the nonfluorescent trans to the fluorescent cis state by light. By using X-ray crystallography, we have determined the structure of dimeric eqFP611 at high resolution (up to 1.1 A). In the far-red emitting eqFP611 variant d2RFP630, which carries an additional Asn143Ser mutation, the chromophore resides predominantly (approximately 80%) in the cis isomeric state, and in RFP639, which has Asn143Ser and Ser158Cys mutations, the chromophore is found completely in the cis form. The pronounced red shift of excitation and emission maxima of RFP639 can thus unambiguously be assigned to trans-cis isomerization of the chromophore. Among RFPs, eqFP611 is thus unique because its chromophore is highly fluorescent in both the cis and trans isomeric forms. 相似文献
46.
Determination of sialic acids released from glycoproteins using capillary zone electrophoresis/electrospray ionization mass spectrometry 总被引:3,自引:0,他引:3
A simple method for the determination of the two most abundant sialic acids released from glycoproteins based on CZE-MS is presented. Several parameters like BGE with various organic modifiers and sheath liquids were studied with respect to their suitability for the fast and easy analysis of the selected compounds by CZE-MS. Finally, a BGE containing 10 mM ammonium acetate allowed the quantification of N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) in glycoproteins as well as human plasma samples. LOD and LOQ were 2 microg/mL and 6 microg/mL, respectively. 相似文献
47.
Lidija Fras Zemljič Zdenka Peršin Per Stenius Karin Stana Kleinschek 《Cellulose (London, England)》2008,15(5):681-690
The influence of peroxide bleaching and slack-mercerization on the amount of acidic groups in regenerated fibres (viscose,
modal and lyocell) were studied. Conductometric titration was used to determine the total content of acidic carboxylic groups.
Polyelectrolyte titration was used for surface and total charge determination, and to obtain information about the charge
distribution and accessibilities of charged groups. Changes in fibre crystallinity to pre-treatment processes were characterized
using iodine sorption (Schwertassek method) and correlated to treatments and the amount of carboxylic groups. For all three
types of fibres the amount of accessible carboxyl groups was lowered by an increase in the degree of crystallinity. Bleaching
with hydrogen peroxide causes some oxidative cellulose damage and, therefore, a larger amount of carboxyl groups (presumably
formed at the end of cellulose chains). Slack-mercerization did not significantly change the total amount of acidic groups
in the fibres, but their accessibility to cationic polyelectrolytes, in particular to polymers with high molecular weight
was substantially lowered.
Lidija Fras Zemljič, Zdenka Peršin, and Karin Stana Kleinschek are the members of the European Polysaccharide Network of Excellence
(EPNOE). 相似文献
48.
49.
Pierozan MK Oestreicher EG Oliveira JV Oliveira D Treichel H Cansian RL 《Applied biochemistry and biotechnology》2011,165(1):75-86
The objective of this study was to provide some features on immobilization and partial characterization of lipases from wheat
seeds. The optimum pH and temperature were found to be 5.5 and 32–37 °C, respectively. The stability of the concentrated enzymatic
extract to high temperatures (25, 35, 45, and 55 °C) showed that the incubation of the extract at 55 °C led to its complete
inactivation. The concentrated enzymatic extract kept 90% of its hydrolytic and esterification activities until 70 and 40 days
of storage at 4 °C, respectively. The extract presented higher hydrolytic specificity to substrates of medium and long chains
and higher esterification affinity to fatty acids of short and medium chains and alcohols with two and three carbon atoms.
After the immobilization process using activated coal and sodium alginate as supports, an enhancement of about threefold in
lipase activity was observed. The development of the present work permitted us to point out some characteristics of lipases
from wheat seeds necessary for the proposition of new future industrial applications for this important biocatalyst. 相似文献