Coconut Carbon Dots: Progressive Large-Scale Synthesis, Detailed Biological Activities and Smart Sensing Aptitudes towards Tyrosine

In the recent era, carbon dots (C-dots) have been extensively considered as a potential tool in drug delivery analysis. However, there have been fewer reports in the literature on their application in the sensing of amino acids. As part of our ongoing research on coconut-husk-derived C-dots, we synthesized C-dots under different temperature conditions and utilized them in the field of amino acid sensing and found them to be highly selective and sensitive towards tyrosine. The detailed characterization of the prepared C-dots was carried out. The developed C-dots exhibit good values of quantum yield. BSA, HSA and glutamic acid were utilized to explore the binding efficiency of C-dots with biologically active components. Hemolysis, blood clotting index activity and cell viability assays using the prepared C-dots were evaluated and they were found to be biocompatible. Therefore, the C-dots described in this work have high potential to be utilized in the field of amino acid sensing, especially L-tyrosine. The limit of detection and the binding constant for the developed C-dots in the presence of tyrosine were found to be 0.96 nM and 296.38 nM−1, respectively. The efficiency of the developed C-dots was also investigated in the presence of various other amino acids and different water mediums in order to enhance the working scope of the developed sensors.

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Electrochemical Amino Acid Sensing: A Review on Challenges and Achievements

Biosensors ◽

10.3390/bios11120502 ◽

2021 ◽

Vol 11 (12) ◽

pp. 502

Author(s):

Kaveh Moulaee ◽

Giovanni Neri

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Performance Metrics ◽

Electrochemical Sensors ◽

Dynamic Range ◽

Limit Of Detection ◽

Amino Acid Level ◽

Detection Sensitivity ◽

Real Sample Analysis ◽

Amino Acid Sensing

The rapid growth of research in electrochemistry in the last decade has resulted in a significant advancement in exploiting electrochemical strategies for assessing biological substances. Among these, amino acids are of utmost interest due to their key role in human health. Indeed, an unbalanced amino acid level is the origin of several metabolic and genetic diseases, which has led to a great need for effective and reliable evaluation methods. This review is an effort to summarize and present both challenges and achievements in electrochemical amino acid sensing from the last decade (from 2010 onwards) to show where limitations and advantages stem from. In this review, we place special emphasis on five well-known electroactive amino acids, namely cysteine, tyrosine, tryptophan, methionine and histidine. The recent research and achievements in this area and significant performance metrics of the proposed electrochemical sensors, including the limit of detection, sensitivity, stability, linear dynamic range(s) and applicability in real sample analysis, are summarized and presented in separate sections. More than 400 recent scientific studies were included in this review to portray a rich set of ideas and exemplify the capabilities of the electrochemical strategies to detect these essential biomolecules at trace and even ultra-trace levels. Finally, we discuss, in the last section, the remaining issues and the opportunities to push the boundaries of our knowledge in amino acid electrochemistry even further.

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Analogues of the cholecystokinin octapeptide modified in the central part of the molecule

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19911963 ◽

1991 ◽

Vol 56 (9) ◽

pp. 1963-1970 ◽

Cited By ~ 3

Author(s):

Jan Hlaváček ◽

Václav Čeřovský ◽

Jana Pírková ◽

Pavel Majer ◽

Lenka Maletínská ◽

...

Keyword(s):

Amino Acid ◽

Biological Activities ◽

Point Of View ◽

Biologically Active ◽

Side Chain ◽

Amino Acid Residues ◽

Cholecystokinin Octapeptide ◽

Biological Tests ◽

Biological Potency ◽

Biologically Active Conformation

In a series of analogues of the cholecystokinin octapeptide (CCK-8) the amino acid residues were gradually modified by substituting Gly by Pro in position 4, Trp by His in position 5, Met by Cle in position 6, or the Gly residue was inserted between Tyr and Met in positions 2 and 3 of the peptide chain, and in the case of the cholecystokinin heptapeptide (CCK-7) the Met residues were substituted by Nle or Aib. These peptides were investigated from the point of view of their biological potency in the peripheral and central region. From the results of the biological tests it follows that the modifications carried out in these analogues and in their Nα-Boc derivatives mean a suppression of the investigated biological activities by 2-3 orders of magnitude (at a maximum dose of the tested substance of 2 . 10-2 mg per animal).This means that a disturbance of the assumed biologically active conformation of CCK-8, connected with a considerable decrease of the biological potency of the molecule, takes place not only after introduction of the side chain into its centre (substitution of Gly4), but also after the modification of the side chains of the amino acids or by extension of the backbone in further positions around this central amino acid.

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Changes in Amino Acid Profiles and Bioactive Compounds of Thai Silk Cocoons as Affected by Water Extraction

Molecules ◽

10.3390/molecules26072033 ◽

2021 ◽

Vol 26 (7) ◽

pp. 2033

Author(s):

Chuleeporn Bungthong ◽

Sirithon Siriamornpun

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Biological Activities ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Silk Protein ◽

Extraction Time ◽

Antioxidant Power ◽

Silk Cocoon ◽

Amino Acid Profiles

Silk proteins have many advantageous components including proteins and pigments. The proteins—sericin and fibroin—have been widely studied for medical applications due to their good physiochemical properties and biological activities. Various strains of cocoon display different compositions such as amino-acid profiles and levels of antioxidant activity. Therefore, the objectives of this study were to find a suitable silk protein extraction method to obtain products with chemical and biological properties suitable as functional foods in two strains of Bombyx mori silk cocoon (Nangsew strains; yellow cocoon) and Samia ricini silk cocoon (Eri strains; white cocoon) extracted by water at 100 °C for 2, 4, 6 and 8 h. The results showed that Nangsew strains extracted for 6 h contained the highest amounts of protein, amino acids, total phenolics (TPC) and total flavonoids (TFC), plus DPPH radical-scavenging activity, ABTS radical scavenging capacity, and ferric reducing antioxidant power (FRAP), anti-glycation, α-amylase and α-glucosidase inhibition. The longer extraction time produced higher concentrations of amino acids, contributing to sweet and umami tastes in both silk strains. It seemed that the bitterness decreased as the extraction time increased, resulting in improvements in the sweetness and umami of silk-protein extracts.

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Hepatoprotective Effect of Mixture of Dipropyl Polysulfides in Concanavalin A-Induced Hepatitis

Nutrients ◽

10.3390/nu13031022 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1022

Author(s):

Dragana Arsenijevic ◽

Bojana Stojanovic ◽

Jelena Milovanovic ◽

Aleksandar Arsenijevic ◽

Milos Simic ◽

...

Keyword(s):

Concanavalin A ◽

Messenger Rna ◽

T Regulatory Cells ◽

Mononuclear Cells ◽

Biological Activities ◽

Biologically Active ◽

Organosulfur Compounds ◽

Liver Inflammation ◽

Regulatory Cells ◽

Active Components

The main biologically active components of plants belonging to the genus Allium, responsible for their biological activities, including anti-inflammatory, antioxidant and immunomodulatory, are organosulfur compounds. The aim of this study was to synthetize the mixture of dipropyl polysulfides (DPPS) and to test their biological activity in acute hepatitis. C57BL/6 mice were administered orally with DPPS 6 h before intravenous injection of Concanavalin A (ConA). Liver inflammation, necrosis and hepatocytes apoptosis were determined by histological analyses. Cytokines in liver tissue were determined by ELISA, expression of adhesive molecules and enzymes by RT PCR, while liver mononuclear cells were analyzed by flow cytometry. DPPS pretreatment significantly attenuated liver inflammation and injury, as evidenced by biochemical and histopathological observations. In DPPS-pretreated mice, messenger RNA levels of adhesion molecules and NADPH oxidase complex were significantly reduced, while the expression of SOD enzymes was enhanced. DPPS pretreatment decreased protein level of inflammatory cytokines and increased percentage of T regulatory cells in the livers of ConA mice. DPPS showed hepatoprotective effects in ConA-induced hepatitis, characterized by attenuation of inflammation and affection of Th17/Treg balance in favor of T regulatory cells and implicating potential therapeutic usage of DPPS mixture in inflammatory liver diseases.

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Determination of amino acids in human biological fluids by high-performance liquid chromatography: critical review

Amino Acids ◽

10.1007/s00726-021-03002-x ◽

2021 ◽

Author(s):

Grażyna Gałęzowska ◽

Joanna Ratajczyk ◽

Lidia Wolska

Keyword(s):

Amino Acids ◽

Amino Acid ◽

High Performance ◽

Hplc Analysis ◽

Limit Of Detection ◽

Biological Fluids ◽

Analytical Techniques ◽

Epidemiological Studies ◽

Preparation Conditions

AbstractThe quantitation and qualification of amino acids are most commonly used in clinical and epidemiological studies, and provide an excellent way of monitoring compounds in human fluids which have not been monitored previously, to prevent some diseases. Because of this, it is not surprising that scientific interest in evaluating these compounds has resurfaced in recent years and has precipitated the development of a multitude of new analytical techniques. This review considers recent developments in HPLC analytics on the basis of publications from the last few years. It helps to update and systematize knowledge in this area. Particular attention is paid to the progress of analytical methods, pointing out the advantages and drawbacks of the various techniques used for the preparation, separation and determination of amino acids. Depending on the type of sample, the preparation conditions for HPLC analysis change. For this reason, the review has focused on three types of samples, namely urine, blood and cerebrospinal fluid. Despite time-consuming sample preparation before HPLC analysis, an additional derivatization technique should be used, depending on the detection technique used. There are proposals for columns that are specially modified for amino acid separation without derivatization, but the limit of detection of the substance is less beneficial. In view of the fact that amino acid analyses have been performed for years and new solutions may generate increased costs, it may turn out that older proposals are much more advantageous.

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Transforming growth factor alpha: mutation of aspartic acid 47 and leucine 48 results in different biological activities.

Molecular and Cellular Biology ◽

10.1128/mcb.8.3.1247 ◽

1988 ◽

Vol 8 (3) ◽

pp. 1247-1252 ◽

Cited By ~ 35

Author(s):

E Lazar ◽

S Watanabe ◽

S Dalton ◽

M B Sporn

Keyword(s):

Amino Acids ◽

Biological Activity ◽

Amino Acid ◽

Growth Factor ◽

Aspartic Acid ◽

Transforming Growth Factor ◽

Biologically Active ◽

Single Amino Acid ◽

Transforming Growth Factor Alpha ◽

Factor Alpha

To study the relationship between the primary structure of transforming growth factor alpha (TGF-alpha) and some of its functional properties (competition with epidermal growth factor (EGF) for binding to the EGF receptor and induction of anchorage-independent growth), we introduced single amino acid mutations into the sequence for the fully processed, 50-amino-acid human TGF-alpha. The wild-type and mutant proteins were expressed in a vector by using a yeast alpha mating pheromone promoter. Mutations of two amino acids that are conserved in the family of the EGF-like peptides and are located in the carboxy-terminal part of TGF-alpha resulted in different biological effects. When aspartic acid 47 was mutated to alanine or asparagine, biological activity was retained; in contrast, substitutions of this residue with serine or glutamic acid generated mutants with reduced binding and colony-forming capacities. When leucine 48 was mutated to alanine, a complete loss of binding and colony-forming abilities resulted; mutation of leucine 48 to isoleucine or methionine resulted in very low activities. Our data suggest that these two adjacent conserved amino acids in positions 47 and 48 play different roles in defining the structure and/or biological activity of TGF-alpha and that the carboxy terminus of TGF-alpha is involved in interactions with cellular TGF-alpha receptors. The side chain of leucine 48 appears to be crucial either indirectly in determining the biologically active conformation of TGF-alpha or directly in the molecular recognition of TGF-alpha by its receptor.

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Activation of the SPS Amino Acid-Sensing Pathway in Saccharomyces cerevisiae Correlates with the Phosphorylation State of a Sensor Component, Ptr3

Molecular and Cellular Biology ◽

10.1128/mcb.00929-07 ◽

2007 ◽

Vol 28 (2) ◽

pp. 551-563 ◽

Cited By ~ 47

Author(s):

Zhengchang Liu ◽

Janet Thornton ◽

Mário Spírek ◽

Ronald A. Butow

Keyword(s):

Saccharomyces Cerevisiae ◽

Amino Acids ◽

Amino Acid ◽

Nuclear Translocation ◽

Proteolytic Processing ◽

Casein Kinase I ◽

Positive Regulators ◽

Amino Acid Permeases ◽

Amino Acid Sensing ◽

Amino Acid Sensor

ABSTRACT Cells of the budding yeast Saccharomyces cerevisiae sense extracellular amino acids and activate expression of amino acid permeases through the SPS-sensing pathway, which consists of Ssy1, an amino acid sensor on the plasma membrane, and two downstream factors, Ptr3 and Ssy5. Upon activation of SPS signaling, two transcription factors, Stp1 and Stp2, undergo Ssy5-dependent proteolytic processing that enables their nuclear translocation. Here we show that Ptr3 is a phosphoprotein whose hyperphosphorylation is increased by external amino acids and is dependent on Ssy1 but not on Ssy5. A deletion mutation in GRR1, encoding a component of the SCFGrr1 E3 ubiquitin ligase, blocks amino acid-induced hyperphosphorylation of Ptr3. We found that two casein kinase I (CKI) proteins, Yck1 and Yck2, previously identified as positive regulators of SPS signaling, are required for hyperphosphorylation of Ptr3. Loss- and gain-of-function mutations in PTR3 result in decreased and increased Ptr3 hyperphosporylation, respectively. We found that a defect in PP2A phosphatase activity leads to the hyperphosphorylation of Ptr3 and constitutive activation of SPS signaling. Two-hybrid analysis revealed interactions between the N-terminal signal transduction domain of Ssy1 with Ptr3 and Yck1. Our findings reveal that CKI and PP2A phosphatase play antagonistic roles in SPS sensing by regulating Ptr3 phosphorylation.

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AMINO ACID COMPOSITION OF LEAVES OF THREE SPECIES OF ARTEMISIA L. GROWING IN THE ELTON REGION

chemistry of plant raw material ◽

10.14258/jcprm.2021038736 ◽

2021 ◽

pp. 219-225

Author(s):

Галина Табаленкова

Keyword(s):

Amino Acids ◽

Czech Republic ◽

Amino Acid ◽

Dry Weight ◽

Biologically Active ◽

Raw Material ◽

Buffer System ◽

Amino Acid Analyzer ◽

Growing Conditions ◽

High Level

The results of studies of the qualitative composition and quantitative content of amino acids (AAs) in the leaves of three plant species of the genus Artemisia, widespread in the Elton region, were presented. Protein AAs were determined on an AAA T-339 amino acid analyzer (Czech Republic) after hydrolysis of a sample in 6N HCl at 105 °C for 24 h, free AAs – on an AAA-400 amino acid analyzer (Czech Republic) in a lithium buffer system. The protein AAs amount varied from 66 mg / g in A. lerchiana to 113 mg / g dry weight in A. santonica. 17 AAs were found in composition of these species, aspartic and glutamic acids were dominant. The content of free AAs varied from 4.4 mg / g in A. santonica to 8.3 mg / g dry weight in A. pauciflora. 14 AAs have been identified, among them proline was the predominant free AA. The share of proline was 75-81% of the total free AAs. Among the minor components, 3-4 compounds with a content above 2% dominated. The free AAs contain 3 non-proteinogenic ones (ornithine, citruline, and γ-aminobutyric acid). A. lerchiana and A. pauciflora species were similar in protein and free amino acids, probably due to the same growing conditions. A high level of free proline, together with a complex of biologically active substances in Artemisia species, which grow abundantly in the Elton region, allow to consider the possibility of their use as a medicinal raw material.

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A Review of Isolation, Chemical Properties, and Bioactivities of Polysaccharides from Bletilla striata

BioMed Research International ◽

10.1155/2020/5391379 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Xiaolong Ji ◽

Mingsong Yin ◽

Hui Nie ◽

Yanqi Liu

Keyword(s):

Structural Characterization ◽

Functional Foods ◽

Biological Activities ◽

Chemical Properties ◽

Biologically Active ◽

Active Components ◽

Bletilla Striata ◽

Extraction Separation ◽

Hemostatic Effects

Recently, polysaccharides from Bletilla striata, a member of the orchidaceous family, aroused the wide interest of people, especially their isolation, chemical properties, and bioactivities. It is reported that these polysaccharides are the most important biologically active components of B. striata, exhibiting various biological activities, such as immunomodulatory, antioxidant, antifibrotic, and hemostatic effects. This review appraised the available literatures which described different aspects of B. striata polysaccharides, including the extraction, separation, purification, structural characterization, and biological activities. We expect to lay the foundation for further investigation of the application of B. striata polysaccharides in the field of functional foods and biomedicine.

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