scholarly journals The Importance of 6-Aminohexanoic Acid as a Hydrophobic, Flexible Structural Element

2021 ◽  
Vol 22 (22) ◽  
pp. 12122
Author(s):  
Agnieszka Markowska ◽  
Adam Roman Markowski ◽  
Iwona Jarocka-Karpowicz
Keyword(s):  
Amino Acid ◽  
Chemical Synthesis ◽  
Biologically Active ◽  
Flexible Structure ◽  
Amino Group ◽  
Structural Element ◽  
Synthetic Fibers ◽  
Active Structures ◽  
Modified Peptides

6-aminohexanoic acid is an ω-amino acid with a hydrophobic, flexible structure. Although the ω-amino acid in question is mainly used clinically as an antifibrinolytic drug, other applications are also interesting and important. This synthetic lysine derivative, without an α-amino group, plays a significant role in chemical synthesis of modified peptides and in the polyamide synthetic fibers (nylon) industry. It is also often used as a linker in various biologically active structures. This review concentrates on the role of 6-aminohexanoic acid in the structure of various molecules.

A serum protease cleaves proANF into a 14-kilodalton peptide and ANF

1987 ◽  
Vol 252 (1) ◽  
pp. E147-E151
Author(s):  
K. D. Bloch ◽  
J. B. Zisfein ◽  
M. N. Margolies ◽  
C. J. Homcy ◽  
J. G. Seidman ◽  
...  
Keyword(s):  
Amino Acid ◽  
Culture Medium ◽  
Rat Plasma ◽  
Biologically Active ◽  
Amino Terminal ◽  
Isolation And Characterization ◽  
Amino Acid Precursor ◽  
Acid Precursor

Proatrial natriuretic factor (proANF), the 126-amino acid precursor of ANF, is the major storage form in mammalian atria. In contrast, two ANF peptides containing the 28- and 24-carboxyterminal residues of proANF have been isolated from rat plasma. Whether the cleavage of proANF in vivo to these ANF peptides occurs during or after its release into the circulation has not been determined. The latter possibility was suggested by our previous study where, by using a cultured rat cardiocyte preparation, we demonstrated that proANF is secreted intact into the culture medium. We now report that serum, but not plasma, contains a protease that specifically cleaves the 17-kdalton proANF to a 14-kdalton amino-terminal peptide and the carboxyterminal 3-kdalton circulating forms of ANF. The role of this proANF-cleaving enzyme in the generation of the biologically active ANF peptides remains to be defined. Its isolation and characterization should provide insights into its site of production and whether in vivo it is involved in the processing of circulating proANF.

scholarly journals The Rx Gene Confers Resistance to a Range of Potexviruses in Transgenic Nicotiana Plants

2008 ◽  
Vol 21 (9) ◽  
pp. 1154-1164 ◽  
Author(s):  
Isabelle Baurès ◽  
Thierry Candresse ◽  
Aymeric Leveau ◽  
Abdelhafid Bendahmane ◽  
Bénédicte Sturbois
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Mosaic Virus ◽  
Potato Virus X ◽  
Structural Element ◽  
Cymbidium Mosaic Virus ◽  
Complex Picture ◽  
Molecular Machinery ◽  
White Clover Mosaic Virus

Rx-mediated resistance was analyzed in Rx-expressing transgenic Nicotiana plants. The infection outcome of nine Potato virus X isolates mutated at amino acid positions 121 and 127 of the coat protein (CP) confirmed the key role of these amino acids but provided a more complex picture than previously reported. In particular, in Rx-expressing Nicotiana spp., eliciting activity modulated by amino acid 121 was conditioned by the nature of amino acid 127. These results suggest that the specificity of recognition might be modulated by host factors that are somehow subtly modified between Rx-expressing potato and Rx-expressing transgenic Nicotiana plants. Moreover, the CP of three Potexviruses, Narcissus mosaic virus (NMV), White clover mosaic virus (WClMV), and Cymbidium mosaic virus (CymMV), are all recognized by the Rx-based machinery and able to trigger an Rx-dependant hypersensitive response. A smaller elicitor of 90 amino acids was identified in the CP of NMV and WClMV, which contains the previously identified key positions 121 and 127. This elicitor is only weakly conserved (approximately 40% identity) among the CP of the various recognized viruses, suggesting that the Rx molecular machinery targets a conserved structural element of the Potexvirus CP rather than a conserved amino acid motif.

scholarly journals D-Serine Production, Degradation, and Transport in ALS: Critical Role of Methodology

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
John P. Crow ◽  
John C. Marecki ◽  
Misty Thompson
Keyword(s):  
Amino Acid ◽  
Intracellular Transport ◽  
Critical Role ◽  
Receptor Activation ◽  
Biologically Active ◽  
Receptor Affinity ◽  
Per Se ◽  
The Brain

In mammalian systems, D-serine is perhaps the most biologically active D-amino acid described to date. D-serine is a coagonist at the NMDA-receptor, and receptor activation is dependent on D-serine binding. Because D-serine binding dramatically increases receptor affinity for glutamate, it can produce excitotoxicity without any change in glutamateper se. D-serine is twofold higher in the spinal cords of mSOD1 (G93A) ALS mice, and the deletion of serine racemase (SR), the enzyme that produces D-serine, results in an earlier onset of symptoms, but with a much slower rate of disease progression. Localization studies within the brain suggest that mSOD1 and subsequent glial activation could contribute to the alterations in SR and D-serine seen in ALS. By also degrading both D-serine and L-serine, SR appears to be a prime bidirectional regulator of free serine levelsin vivo. Therefore, accurate and reproducible measurements of D-serine are critical to understanding its regulation by SR. Several methods for measuring D-serine have been employed, and significant issues related to validation and standardization remain unresolved. Further insights into the intracellular transport and tissue-specific compartmentalization of D-serine within the CNS will aid in the understanding of the role of D-serine in the pathogenesis of ALS.

Proteases and posttranslational processing of prohormones: a review

1983 ◽  
Vol 61 (7) ◽  
pp. 501-515 ◽  
Author(s):  
Claude Lazure ◽  
Nabil G. Seidah ◽  
Didier Pélaprat ◽  
Michel Chrétien
Keyword(s):  
Amino Acid ◽  
Current Knowledge ◽  
Secretory Granules ◽  
Basic Amino Acid ◽  
Biologically Active ◽  
Maturation Process ◽  
Active Peptides ◽  
Biologically Active Peptides ◽  
Precursor Molecules

Pioneering work on insulin and on lipotropin, published in 1967, led to the formulation of the hypothesis that biologically active peptides such as peptide hormones are derived from larger precursor molecules by enzymatic cleavage at basic amino acid pairs. Since then, an ever-increasing number of hormones and active peptides including neuropeptides have been found to be contained within the sequence of a larger precursor protein and are released by limited proteolytic cleavage. The hypothesis concerning the posttranslational maturation of precursor molecules into smaller active entities is now firmly established in many tissues (e.g., pituitary gland, pancreas) and for all kinds of organisms (e.g. mammals, fish), though the nature of the enzyme(s) responsible for this maturation process still remains unknown. This article presents current knowledge of the intracellular processing of precursor molecules, especially the conversion of prohormone to hormone. The discussion deals principally with the evidences concerning the localization of the maturation process mainly in the secretory granules, the role of basic amino acid pairs at the cleavage site, and the possible involvement of serine and (or) thiol endopeptidases in that process.

A Cyclotide Isolated from Noisettia orchidiflora (Violaceae)

Planta Medica ◽  
2018 ◽  
Vol 84 (12/13) ◽  
pp. 947-952 ◽  
Author(s):  
Antonio Bobey ◽  
Meri Pinto ◽  
Eduardo Cilli ◽  
Norberto Lopes ◽  
Vanderlan Bolzani
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Primary Structure ◽  
Plant Protection ◽  
Enzymatic Digestion ◽  
Flowering Plants ◽  
Biologically Active ◽  
Alkylation Reactions ◽  
Tof Ms

AbstractBiologically active cyclotides have been found on some flowering plants species and are involved in the role of the plant protection. As part of studies focusing on peptides from Brazilian plant species, we are reporting the detection by LC-MS of several cyclotides from leaves and stems of Noisettia orchidiflora (Violaceae). From stems it was possible to isolate and characterize a cyclotide named Nor A. Its primary structure (amino acid sequence) was established by MALDI-TOF-MS, based on the y- and b-type ion series, after reduction and alkylation reactions, as well as enzymatic digestion using the enzymes endoproteinase glutamic acid (endoGlu-C), trypsin, and chymotrypsin. Furthermore, the amino acid analysis was also described.

scholarly journals The role of cysteine-150 in the structure and activity of rat liver S-adenosyl-l-methionine synthetase

1991 ◽  
Vol 274 (1) ◽  
pp. 225-229 ◽  
Author(s):  
M A Pajares ◽  
F J Corrales ◽  
P Ochoa ◽  
J M Mato
Keyword(s):  
Amino Acid ◽  
Active Site ◽  
Urea Treatment ◽  
Atp Binding Site ◽  
Modified Peptides ◽  
Activity Loss ◽  
Main Activity ◽  
Activity Decrease ◽  
Structure And Activity

The present paper reports the tryptic digestion of N-ethylmaleimide-treated S-adenosyl-L-methionine synthetase (high- and low-Mr forms) and the isolation of the modified peptides by h.p.l.c. There is only one site modified after 5 min incubation, and the modification at this site correlates with the main activity decrease. The amino acid composition of this peptide was determined, and its localization in the sequence shows the modified residue as cysteine-150, which is located close to the putative ATP-binding site. Modification of the enzyme for 20 min led to the appearance of a second labelled peptide, which seems to be responsible for about a further 10% of the activity loss. The modification by N-ethylmaleimide of the enzyme was partially prevented in the presence of adenosine 5′-[beta gamma-imido]triphosphate and methionine, further supporting the hypothesis that the modified residues lie within the active site. Urea treatment of the enzyme, followed by modification with N-ethylmaleimide, produces the modification of 7 of the 10 cysteine residues present in the sequence. The results obtained were the same for either of the isoforms.

scholarly journals The role of chemical synthesis in developing RiPP antibiotics

2021 ◽  
Vol 50 (7) ◽  
pp. 4245-4258
Author(s):  
Sam M. Rowe ◽  
David R. Spring
Keyword(s):  
Chemical Synthesis ◽  
Lasso Peptides ◽  
Modified Peptides

This tutorial review discusses the potential of ribosomally synthesised and post-translationally modified peptides (RiPPs) as antimicrobials and looks at the chemical synthesis of three classes of RiPP: lasso peptides, cyclotides, and lanthipeptides.

Bioavailability of naringenin chalcone in humans after ingestion of cherry tomatoes

2020 ◽  
Vol 90 (5-6) ◽  
pp. 411-416 ◽  
Author(s):  
Carina Kolot ◽  
Ana Rodriguez-Mateos ◽  
Rodrigo Feliciano ◽  
Katharina Bottermann ◽  
Wilhelm Stahl
Keyword(s):  
Plasma Levels ◽  
Average Concentration ◽  
Biologically Active ◽  
Thiol Groups ◽  
Structural Element ◽  
Active Molecule ◽  
Reactive Center ◽  
Average Maximum ◽  
Alpha Beta ◽  
Cherry Tomatoes

Abstract. Chalcones are a type of flavonoids characterized by an α-β unsaturated structural element which may react with thiol groups to activate pathways such as the Nrf2-Keap-1 system. Naringenin chalcone is abundant in the diet but little is known about its bioavailability. In this work, the bioavailability of naringenin chalcone from tomatoes was investigated in a group of healthy men (n=10). After ingestion of 600 grams of tomatoes providing a single dose of 17.3 mg naringenin chalcone, 0.2 mg of naringenin, and 195 mg naringin plasma levels of free and conjugated naringenin and naringenin chalcone (glucuronide and sulfate) were analyzed by UHPLC-QTOF-MS at 0.5, 1, 3, and 6 h post-consumption. Plasma levels of conjugated naringenin increased to about 12 nmol/L with a maximum at about 3 h. Concentrations of free naringenin hardly elevated above baseline. Plasma levels of free and conjugated naringenin chalcone significantly increased. A maximum of the conjugated chalcone was reached at about 3 h after ingestion with an average concentration of about 0.5 nmol/L. No free chalcone was detectable at baseline but low amounts of the unconjugated compound could be detected with an average maximum of 0.8 nmol/L at about 1 h after ingestion. The data demonstrate that naringenin chalcone is bioavailable in humans from cherry tomatoes as a dietary source. However, availability is poor and intramolecular cyclisation as well as extended metabolism likely contribute to the inactivation of the reactive alpha-beta unsaturated reactive center as well as the excretion of the biologically active molecule, respectively.

Predicting the Strength of Stacking Interactions Between Heterocycles and Aromatic Amino Acid Side Chains

2019 ◽  
Author(s):  
Andrea N. Bootsma ◽  
Analise C. Doney ◽  
Steven Wheeler
Keyword(s):  
Amino Acid ◽  
Binding Sites ◽  
Aromatic Amino Acid ◽  
Aromatic Amino Acids ◽  
Biologically Active ◽  
Side Chains ◽  
Stacking Interactions ◽  
Inhibitor Binding ◽  
Protein Binding Sites ◽  
Amino Acid Side Chains

<p>Despite the ubiquity of stacking interactions between heterocycles and aromatic amino acids in biological systems, our ability to predict their strength, even qualitatively, is limited. Based on rigorous <i>ab initio</i> data, we have devised a simple predictive model of the strength of stacking interactions between heterocycles commonly found in biologically active molecules and the amino acid side chains Phe, Tyr, and Trp. This model provides rapid predictions of the stacking ability of a given heterocycle based on readily-computed heterocycle descriptors. We show that the values of these descriptors, and therefore the strength of stacking interactions with aromatic amino acid side chains, follow simple predictable trends and can be modulated by changing the number and distribution of heteroatoms within the heterocycle. This provides a simple conceptual model for understanding stacking interactions in protein binding sites and optimizing inhibitor binding in drug design.</p>

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