Carbodiimide-mediated conjugation of hippuric acid to concanavalin A: retention of ligand binding and hemagglutinating activities

1986 ◽  
Vol 64 (12) ◽  
pp. 1366-1371 ◽  
Author(s):  
James F. Preston III ◽  
Ronald S. Hencin
Keyword(s):  
Biological Activity ◽  
Reaction Time ◽  
Ligand Binding ◽  
Small Molecules ◽  
Concanavalin A ◽  
Hippuric Acid ◽  
Carboxyl Groups ◽  
Cross Linking ◽  
Amino Groups ◽  
Hemagglutination Titer

Conditions for conjugating small molecules with reactive carboxyl groups to concanavalin A (ConA), with retention of biological activity of the lectin, are described. Hippuric acid was conjugated to reactive amino groups on ConA with N-ethyl-N′-(dimethylaminopropyl)carbodiimide under conditions in which neither inter- nor intra-molecular cross-linking was detectable. These same conditions provided for the loading of variable amounts of hippurate as a function of reaction time; conjugates were synthesized with 9.6 mol hippurate∙mol ConA−1. Conjugation in the presence of 0.1 M phosphate provided a condition for limiting the extent of coupling; only amide linkages were formed. These conjugates retained both the ability to bind ligands and the hemagglutination titer of the native lectin.

scholarly journals Strategies to Functionalize the Anionic Biopolymer Na-Alginate without Restricting Its Polyelectrolyte Properties

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 919 ◽  
Author(s):  
Luca Szabó ◽  
Sandrine Gerber-Lemaire ◽  
Christine Wandrey
Keyword(s):  
Biological Activity ◽  
Biomedical Applications ◽  
Recent Progress ◽  
Analytical Techniques ◽  
Carboxyl Groups ◽  
Cross Linking ◽  
Special Focus ◽  
Hydrogel Formation ◽  
Alginate Hydrogels ◽  
Derivatives Of

The natural anionic polyelectrolyte alginate and its derivatives are of particular interest for pharmaceutical and biomedical applications. Most interesting for such applications are alginate hydrogels, which can be processed into various shapes, self-standing or at surfaces. Increasing efforts are underway to functionalize the alginate macromolecules prior to hydrogel formation in order to overcome the shortcomings of purely ionically cross-linked alginate hydrogels that are hindering the progress of several sophisticated biomedical applications. Particularly promising are derivatives of alginate, which allow simultaneous ionic and covalent cross-linking to improve the physical properties and add biological activity to the hydrogel. This review will report recent progress in alginate modification and functionalization with special focus on synthesis procedures, which completely conserve the ionic functionality of the carboxyl groups along the backbone. Recent advances in analytical techniques and instrumentation supported the goal-directed modification and functionalization.

Influence of Calcium Ions on the Plant Cell Surface: Membrane Fusions and Conformational Changes

1974 ◽  
Vol 32 ◽  
pp. 154-155
Author(s):  
D. James Morré ◽  
Charles E. Bracker ◽  
William J. VanDerWoude
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Conformational Changes ◽  
Calcium Ions ◽  
Surface Membrane ◽  
Carboxyl Groups ◽  
Cross Linking ◽  
Ultrastructural Evidence ◽  
Glycine Max L ◽  
Wall Extensibility

Calcium ions in the concentration range 5-100 mM inhibit auxin-induced cell elongation and wall extensibility of plant stems. Inhibition of wall extensibility requires that the tissue be living; growth inhibition cannot be explained on the basis of cross-linking of carboxyl groups of cell wall uronides by calcium ions. In this study, ultrastructural evidence was sought for an interaction of calcium ions with some component other than the wall at the cell surface of soybean (Glycine max (L.) Merr.) hypocotyls.

COMPARATIVE STUDIES OF THE POTENTIATION OF CORTICOTROPHIN ACTIVITY BY SEVERAL INACTIVE DERIVATIVES

1963 ◽  
Vol 42 (2) ◽  
pp. 209-213 ◽  
Author(s):  
Arthur I. Cohen ◽  
Edward H. Frieden
Keyword(s):  
Biological Activity ◽  
Comparative Studies ◽  
Free Amino ◽  
Hormonal Activity ◽  
Amino Groups

ABSTRACT A number of corticotrophin analogues have been prepared, some of which potentiate the biological activity of the untreated hormone in vitro. The free amino groups of corticotrophin appear to be essential not only for hormonal activity, but also for the interaction of the analogues with the tissue corticotrophin inactivating system which is assumed to account for the potentiating effect.

Broad Assessment of Bioactivity of a Collection of Spiroindane Pyrrolidines Through “Cell Painting”

2020 ◽  
Author(s):  
Zarko Boskovic ◽  
Manvendra Singh ◽  
Zachary Pearson ◽  
Nathan Garza
Keyword(s):  
Biological Activity ◽  
Small Molecules ◽  
Functional Groups ◽  
Organelle Morphology

A collection of small molecules has been synthesized by composing photo-cycloaddition, C-H functionalization, and N-capping strategies. Multidimensional biological fingerprints of molecules comprising this collection have been recorded as changes in cell and organelle morphology. This untargeted, phenotypic approach allowed for a broad assessment of biological activity to be determined. Reproducibility and the magnitude of measured fingerprints revealed activity of several treatments. Reactive functional groups, such as imines, dominated the observed activity. Two non-reactive candidate compounds with distinct bioactivity fingerprints were identified, as well.

Naphthoquinone Derivatives Isolated from Plants: Recent Advances in Biological Activity

2020 ◽  
Vol 20 (19) ◽  
pp. 2019-2035
Author(s):  
Esmaeil Sheikh Ahmadi ◽  
Amir Tajbakhsh ◽  
Milad Iranshahy ◽  
Javad Asili ◽  
Nadine Kretschmer ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Biological Activity ◽  
Small Molecules ◽  
Anticancer Activity ◽  
Clinical Significance ◽  
Phase Ii ◽  
Biological Activities ◽  
Phase Ii Clinical Trials ◽  
Naturally Occurring ◽  
The Subject

Naturally occurring naphthoquinones (NQs) comprising highly reactive small molecules are the subject of increasing attention due to their promising biological activities such as antioxidant, antimicrobial, apoptosis-inducing activities, and especially anticancer activity. Lapachol, lapachone, and napabucasin belong to the NQs and are in phase II clinical trials for the treatment of many cancers. This review aims to provide a comprehensive and updated overview on the biological activities of several new NQs isolated from different species of plants reported from January 2013 to January 2020, their potential therapeutic applications and their clinical significance.

scholarly journals Modulation of phagosome-lysosome fusion in mouse macrophages.

1981 ◽  
Vol 153 (4) ◽  
pp. 1015-1020 ◽  
Author(s):  
M C Kielian ◽  
Z A Cohn
Keyword(s):  
Concanavalin A ◽  
Immune Serum ◽  
Cross Linking ◽  
Activated Macrophages ◽  
Enzymatic Modification ◽  
Inflammatory Agent ◽  
Proteose Peptone ◽  
Mouse Macrophages ◽  
Control Fusion ◽  
Rate Limiting

A previously described fluorescence assay has been used to characterize factors that modulate phagosome-lysosome (P-L) fusion in mouse macrophages. Fusion was not affected by enzymatic modification or by concanavalin A cross-linking of the plasma membrane or by coating the phagocytic particle with concanavalin A or immune serum. Pretreatment of cells with 10-5-10-4 M colchicine, or treatment immediately after ingestion with 1-10 microgram/ml cytochalasin did not alter P-L fusion; implying that the cytoskeleton does not control fusion in a rate-limiting way. Fusion was strikingly elevated in 5-h cultures of activated macrophages from immune-boosted mice. A lower enhancement was seen in cells activated by proteose-peptone, a nonspecific inflammatory agent.

scholarly journals The principle of formaldehyde, alcohol, and acetone titrations. With a discussion of the proof and implication of the zwitterion conception

1934 ◽  
Vol 115 (792) ◽  
pp. 121-141 ◽  
Keyword(s):  
Amino Acids ◽  
Carboxyl Groups ◽  
Recent Discussion ◽  
Amino Groups ◽  
Chemical Methods ◽  
Titration Method ◽  
Physico Chemical ◽  
Empirical Argument ◽  
Chemical Evidence

Consideration of the implications of the zwitterion hypothesis of Bjerrum (1923) makes it desirable to state afresh the principles underlying the methods commonly employed in the titration of amino-acids. Deductions of considerable theoretical importance, cf., e. g ., Calvery (1933) are still being made on the supposition that the alkalimetric formaldehyde titration method of Sørensen (1907) and the corresponding alcohol method of Foreman (1920) and of Willstätter and Waldschmidt-Leitz (1921) estimate the carboxyl groups of amino-acids whilst the acidimetric acetone titration of Linderstrøm-Lang (1928) estimates the amino-groups. Yet the zwitterion hypothesis indicates that this assumption is the reverse of the truth. Discussion is greatly facilitated by collective consideration of recent physico-chemical evidence clarifying the principles upon which these common bio-chemical methods rest. In a recent discussion of two of the titrimetric methods (Van Slyke and Kirk, 1933) the existence of this evidence is ignored, so that it becomes necessary to systematize and elaborate the empirical argument of these authors in the light of the relevant investigations of Grünhut (1919), Cray and Westrip (1925), Michaelis and Mizutani (1925), Birch and Harris (1930, b ), and Levy (1933). At the same time new and useful developments are indicated.

Analysis of Ligand Binding and Cross-Linking of Receptors in Solution and on Cell Surfaces

1991 ◽  
pp. 169-195
Author(s):  
Jon Erickson ◽  
Richard Posner ◽  
Byron Goldstein ◽  
David Holowka ◽  
Barbara Baird
Keyword(s):  
Ligand Binding ◽  
Cross Linking ◽  
Cell Surfaces

scholarly journals Carboxylate-Functionalized P, N-Ligated Cobalt Catalysts for Alkene Hydrosilylation

2020 ◽  
Vol 17 ◽  
Author(s):  
Yangyang Ma ◽  
Jiayun Li ◽  
Ying Bai ◽  
Jiajian Peng
Keyword(s):  
Activation Energy ◽  
Reaction Time ◽  
Efficient Method ◽  
Cobalt Catalysts ◽  
Carboxyl Groups ◽  
Catalytic Hydrosilylation ◽  
P Ligands

: A series of N, P-ligands bearing carboxyl groups has been synthesized. These have been applied in conjunction with cobalt naphthenate in a facile, economic, and efficient method for the catalytic hydrosilylation of alkenes. In the presence of KOtBu as an additive, the reaction time and activation energy are greatly reduced.

Alteration of quaternary structure and biological activity of concanavalin A

1984 ◽  
Vol 3 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Shin-ichi Ishii ◽  
Yukichi Abe ◽  
Isao Tanaka ◽  
Masaki Saito
Keyword(s):  
Biological Activity ◽  
Concanavalin A ◽  
Quaternary Structure
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