Séparation des virotoxines du champignon Amanita virosa et étude comparative de leur interaction sur l'actine in vitro

1984 ◽  
Vol 62 (12) ◽  
pp. 1327-1334 ◽  
Author(s):  
Andrée Turcotte ◽  
Claude Gicquaud ◽  
Marthe Gendreau ◽  
Serge St-Pierre
Keyword(s):  
Amino Acids ◽  
Molecular Interaction ◽  
Cyclic Peptides ◽  
Cytochalasin B ◽  
Biological Properties ◽  
Preparative Hplc ◽  
Minor Importance ◽  
Rate Of Polymerization ◽  
Chaotropic Ions

Cyclic peptides have been extracted with methanol from Amanita virosa and separated by preparative HPLC. Six peptides were obtained: phalloidin and five new peptides recently identified by Faulstich as virotoxins. We have compared the interaction of these six peptides with actin in vitro. They increased the rate of polymerization of actin and protected F-actin against several denaturating agents: proteases, heat, chaotropic ions, cytochalasin B, and DNAse I. The five virotoxins have therefore the same biological properties as phalloidin. However, the differential spectra of interaction between actin and the five virotoxins are different than the differential spectra between actin and phalloidin, thus it appears that the molecular interaction of actin with virotoxins is different than with phalloidin. The five virotoxins have the same activity. Although these virotoxins have different functional groups on amino acids 1 and 7, it is concluded that these two amino acids are of minor importance in the interaction of these peptides with actin.

Sulfur-free parathyroid hormone analogs containing D-amino acids: biological properties in vitro and in vivo

Biochemistry ◽  
1981 ◽  
Vol 20 (25) ◽  
pp. 7246-7250 ◽  
Author(s):  
Michael Rosenblatt ◽  
Marc D. Coltrera ◽  
Gary L. Shepard ◽  
D. A. Gray ◽  
John A. Parsons ◽  
...  
Keyword(s):  
Amino Acids ◽  
Parathyroid Hormone ◽  
Biological Properties ◽  
Hormone Analogs

scholarly journals In Vitro and In Silico Evaluation of Biological Properties of Some 1, 3, 4-Oxadiazole Derivatives Against Streptococcus mutans and Their Interaction With Gbp-C by Molecular Docking

2021 ◽  
Vol 13 (4) ◽  
pp. 142-147
Author(s):  
Behin Omidi ◽  
Yasin SarveAhrabi
Keyword(s):  
Amino Acids ◽  
Molecular Docking ◽  
Hydrogen Bonds ◽  
Streptococcus Mutans ◽  
In Silico ◽  
Antibacterial Properties ◽  
Inhibition Zone ◽  
Biological Properties ◽  
High Concentrations

Background: The need to replace new drug structures for the treatment of resistant strains has become essential. Streptococcus mutans is one of the most important factors in causing tooth decay. Glucan binding protein-C (Gbp-C) is a crucial mobileular floor protein that is worried in biofilm formation, and 1, 3, 4-oxadiazoles are new antibacterial structures. Accordingly, this study focused on assessing in vitro and in silico activity of our previously synthesized compounds of 1, 3, 4-oxadiazole against S. mutans. Methods: To this end, our previously synthesized derivatives were re-synthesized and prepared, and then antibacterial susceptibility tests were used for inhibition zone, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) test values. The molecular docking method was also applied to confirm the effect of compounds in interaction with the Gbp-C of S. mutans. Results: All compounds showed different effects against the bacterial sample. Among these, the most effective ones were related to naphthalene (4d), fluorophenyl (4e), and dimethoxyphenyl (4h) derivatives against S. mutans, respectively. Other compounds also had antibacterial properties but to a lesser extent. In the molecular part, compounds 4d and 4h had the highest affinity to inhibit the GbpC-protein. compound 4d with amino acids ASP and GLN established 402 and 391 hydrogen bonds, respectively, and compound 4h with amino acids SER, GLU, THR, and TRP established 347, 360, 449, and 451 hydrogen bonds, respectively. Conclusions: In general, 1, 3, 4-oxadiazoles containing naphthalene and dimethoxy phenyl functional groups in high concentrations can be good alternatives to the existing drugs for eliminating caries-causing tooth mutants that have drug resistance. It seems that more inhibitory effects can be observed on clinical specimens by adding different purposeful groups and increasing the destructive power of oxadiazole-based compounds.

The Analogs of [D-Har8]Vasopressin with Di- and Trisubstituted Phenylalanine in Position 2; Synthesis and Some Biological Properties

1993 ◽  
Vol 58 (11) ◽  
pp. 2751-2760 ◽  
Author(s):  
Miroslava Žertová ◽  
Zdenko Procházka ◽  
Jiřina Slaninová ◽  
Tomislav Barth ◽  
Pavel Majer ◽  
...  
Keyword(s):  
Amino Acids ◽  
Solid Phase ◽  
Biological Properties ◽  
Phase Method ◽  
Antidiuretic Activity ◽  
Solid Phase Method

Four analogs of vasopressin with non-coded amino acids D-homoarginine (in position 8) and 2,6-di- or 2,4,6-trisubstituted L- or D-phenylalanine (in position 2) were synthesized using the solid phase method on p-methylbenzhydrylamine resin. All the analogs were found to be uterotonic inhibitors, the most potent one in vitro and in vivo being [D-Phe(2,4,6-triMe)2,D-Har8]vasopressin with pA2 values equal to 8.1 and 7.5, respectively. All of them had negligible antidiuretic activity and were weak pressor inhibitors.

Conformational and Biological Properties of Partial Sequences of Glucagon

1973 ◽  
Vol 51 (4) ◽  
pp. 243-248 ◽  
Author(s):  
Richard M. Epand ◽  
Vijaylaxmi Grey
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Biological Properties ◽  
In Vitro Assays ◽  
Adenyl Cyclase Activity ◽  
Amino Acid Fragment ◽  
Acid Fragment ◽  
Carboxyl Terminal ◽  
Derivatives Of

We have investigated the properties of derivatives of the 29-amino-acid polypeptide hormone, glucagon, which had varying numbers of amino acids cleaved from the carboxyl terminal portion of the molecule. These derivatives included a 27-amino-acid fragment made by cleavage of the native molecule with cyanogen bromide and a 23-amino-acid fragment made synthetically. We found both of these derivatives capable of stimulating the conversion of ATP to cyclic AMP in in vitro assays using rat liver homogenates. The concentration of these peptides, which were required to produce enhanced adenyl cyclase activity, was higher than that of glucagon, and in the case of the 1–23 derivative it was several orders of magnitude larger. The requirement for higher concentrations of peptide is expected, as removal of a large portion of the total number of amino acids will proportionately decrease the free energy of dissociation of the peptide from the membrane receptor, thus changing the equilibrium constant for binding by several orders of magnitude. Circular dichroism and ultra-centrifuge studies of these peptides, as well as a 21-amino-acid fragment made by cleavage of the native molecule with carboxypeptidase, indicated that the shorter glucagon analogues have structures similar to that of the native molecule although somewhat less ordered.

IMPROVEMENT OF T-PA PROPERTIES BY MEANS OF SITE DIRECTED MUTAGENESIS

1987 ◽  
Author(s):  
N Haigwood ◽  
E-P Pâques ◽  
G Mullenbach ◽  
G Moore ◽  
L DesJardin ◽  
...  
Keyword(s):  
Amino Acids ◽  
Cleavage Site ◽  
Specific Activity ◽  
Biological Properties ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Mutant Proteins ◽  
C Terminus

The clinical relevance of tissue-plasminogen-activator (t-PA) as a potent thrombolytic agent has recently been established. It has however been recognized that t-PA does not fulfill all conditions required for an ideal thrombolytic pharmaceutical agent; for example, its physiological stability and its short half life in vivo necessitate the use of very large clinical doses. We have therefore attempted to develop novel mutant t-PA proteins with improved properties by creating mutants by site-directed mutagenesis in M13 bacteriophage. Seventeen mutants were designed, cloned, and expressed in CHO cells. Modifications were of three types: alterations to glycosylation sites, truncations of the N- or C-termini, and amino acids changes at the cleavage site utilized to generate the two chain form of t-PA. The mutant proteins were analyzed in vitro for specific activity, fibrin dependence of the plasminogen activation, fibrin affinity, and susceptibility to inhibition by PAI.In brief, the results are: 1) some unglycosylated and partially glycosylated molecules obtained by mutagenesis are characterized by several-fold higher specific activity than wild type t-PA; 2) truncation at the C-terminus by three amino acids yields a molecule with increased fibrin specificity; 3) mutations at the cleavage site lead zo a decreased inhibition by PAI; and 4) recombinants of these genes have been constructed and the proteins were shown to possess multiple improved properties. The use of site directed mutagenesis has proved to be a powerful instrument to modulate the biological properties of t-PA.

The Analogs of 8-D-Homoarginin-vasopressin with O-Substituted Phenylalanine in Position 2: Synthesis and Some Biological Properties

1992 ◽  
Vol 57 (5) ◽  
pp. 1103-1110 ◽  
Author(s):  
Miroslava Žertová ◽  
Zdenko Procházka ◽  
Jiřina Slaninová ◽  
Tomislav Barth ◽  
Pavel Majer ◽  
...  
Keyword(s):  
Amino Acids ◽  
Solid Phase ◽  
Biological Properties ◽  
Antidiuretic Activity

Solid phase methodology on p-methylbenzhydrylamine resin was used for the synthesis of four analogs of vasopressin with the non coded amino acids, D-homoarginine (in position 8) and o-substituted L- or D-phenylalanine (in position 2). [L-Phe(o-Me)2,D-Har8]vasopressin (I), [D-Phe(o-Me)2,D-Har8]vasopressin (II), [L-Phe(o-Et)2,D-Har8]vasopressin (III) and [D-Phe(o-Et)2,D-Har8]vasopressin (IV) were synthesized. All analogs had very low antidiuretic activity. Analogs I and IV were low pressor inhibitors. All analogs were found to be the uterotonic inhibitors, the most potent on in vitro being [D-Phe(o-Et)2,D-Har8]vasopressin with a pA2 = 8.4.

scholarly journals Biological Properties of a Novel Follicle-Stimulating Hormone/Human Chorionic Gonadotropin Chimeric Gonadotropin

Endocrinology ◽  
2006 ◽  
Vol 147 (9) ◽  
pp. 4205-4212 ◽  
Author(s):  
Louise M. Garone ◽  
Elena Ammannati ◽  
Theresa S. Brush ◽  
David J. Fischer ◽  
Enrico Gillio Tos ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Biological Properties ◽  
Glycoprotein Hormone ◽  
Α Subunit ◽  
Recombinant Human Fsh

A chimeric recombinant human gonadotropin, termed C3, demonstrates both follitropic and lutropic bioactivities. The α-subunit construct for C3 is comprised of the recombinant wild-type human glycoprotein hormone α-subunit. The β-subunit DNA construct for C3 encodes residues 1–145 from human chorionic gonadotropin (hCG)-β with the exceptions that FSHβ amino acid 88 (D) is substituted for hCGβ amino acid 94 (R) and FSHβ amino acids 95–108 (TVRGLGPSYCSFGE) are substituted for hCGβ amino acids 101–114 (GGPKDHPLTCDDPR). C3 is a potent FSH and LH agonist able to bind and to signal through FSH and LH receptors in vitro. In in vivo bioassays optimized to quantify each type of activity, C3 was found to have lutropin and follitropin potencies at levels similar to those of recombinant human LH and recombinant human FSH, respectively. In immature rats, C3 was sufficient to support the maturation of normal ovarian follicles. Moreover, a significant portion of follicles matured by C3 ruptured in response to an ovulatory hCG stimulus and gave rise to morphologically normal oocytes. Furthermore, a low dose of C3 promoted weight gain in the rodent uterus, suggesting it also supported preparation for implantation without histological evidence of excessive luteinization of the ovary. In summary, the biological properties of C3 indicate that its chimeric nature has resulted in a fully functional, dual-acting human gonadotropin.

MOLECULAR INTERACTION THROUGH FREE VOLUME AND INTERNAL PRESSURE OF AQUEOUS AMINO ACIDS AT 308.15 K

2014 ◽  
Author(s):  
Amardeep Shende Hemant Baradkar Vilas Tabhane Amardeep Shende Hemant Baradkar Vilas Tabhane ◽  
Keyword(s):  
Amino Acids ◽  
Internal Pressure ◽  
Free Volume ◽  
Molecular Interaction

In vitro Behaviour of Alumina-Hydroxiapatite Composites Coatings

2018 ◽  
Vol 69 (6) ◽  
pp. 1416-1418
Author(s):  
Alexandru Szabo ◽  
Ilare Bordeasu ◽  
Ion Dragos Utu ◽  
Ion Mitelea
Keyword(s):  
Pure Titanium ◽  
Titanium Substrate ◽  
High Strength ◽  
Biological Properties ◽  
Commercially Pure Titanium ◽  
Hvof Spraying ◽  
Before And After ◽  
Sbf Solution ◽  
Oxygen Fuel

Hydroxyapatite (HA) is a very common material used for biomedical applications. Usually, in order to improve its poor mechanical properties is combined or coated with other high-strength materials.The present paper reports the manufacturing and the biocompatibility behaviour of two different biocomposite coatings consisting of alumina (Al2O3) and hydroxyapatite (HA) using the high velocity oxygen fuel (HVOF) spraying method which were deposited onto the surface of a commercially pure titanium substrate. The biological properties of the Al2O3-HA materials were evaluated by in vitro studies. The morphology of the coatings before and after their immersing in the simulated body fluid (SBF) solution was characterized by scanning electron microscopy (SEM). The results showed an important germination of the biologic hydroxyapatite crystallite on the surface of both coatings.

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