Analysis of Amino Acids and Small Peptides

1988 ◽  
pp. 245-283
Author(s):  
Colin Simpson
Keyword(s):  
Amino Acids ◽  
Small Peptides

scholarly journals Selective Recognition of Amino Acids and Peptides by Small Supramolecular Receptors

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 106
Author(s):  
Joana N. Martins ◽  
João Carlos Lima ◽  
Nuno Basílio
Keyword(s):  
Amino Acids ◽  
Selective Recognition ◽  
Great Promise ◽  
Macrocyclic Compounds ◽  
Synthetic Receptors ◽  
Small Peptides ◽  
Molecular Imprinted Polymers ◽  
Polymeric Systems ◽  
Physiological Conditions ◽  
Level Information

To this day, the recognition and high affinity binding of biomolecules in water by synthetic receptors remains challenging, while the necessity for systems for their sensing, transport and modulation persists. This problematic is prevalent for the recognition of peptides, which not only have key roles in many biochemical pathways, as well as having pharmacological and biotechnological applications, but also frequently serve as models for the study of proteins. Taking inspiration in nature and on the interactions that occur between several receptors and peptide sequences, many researchers have developed and applied a variety of different synthetic receptors, as is the case of macrocyclic compounds, molecular imprinted polymers, organometallic cages, among others, to bind amino acids, small peptides and proteins. In this critical review, we present and discuss selected examples of synthetic receptors for amino acids and peptides, with a greater focus on supramolecular receptors, which show great promise for the selective recognition of these biomolecules in physiological conditions. We decided to focus preferentially on small synthetic receptors (leaving out of this review high molecular weight polymeric systems) for which more detailed and accurate molecular level information regarding the main structural and thermodynamic features of the receptor biomolecule assemblies is available.

scholarly journals The conjugation of nonsteroidal anti-inflammatory drugs (NSAID) to small peptides for generating multifunctional supramolecular nanofibers/hydrogels

2013 ◽  
Vol 9 ◽  
pp. 908-917 ◽  
Author(s):  
Jiayang Li ◽  
Yi Kuang ◽  
Junfeng Shi ◽  
Yuan Gao ◽  
Jie Zhou ◽  
...  
Keyword(s):  
Amino Acids ◽  
Critical Concentration ◽  
Therapeutic Agents ◽  
Multiple Roles ◽  
Small Peptides ◽  
Covalent Linkage ◽  
Physiological Conditions ◽  
Racemic Ibuprofen ◽  
Inflammatory Drugs ◽  
Anti Inflammatory

Here we report supramolecular hydrogelators made of nonsteroidal anti-inflammatory drugs (NSAID) and small peptides. The covalent linkage of Phe–Phe and NSAIDs results in conjugates that self-assemble in water to form molecular nanofibers as the matrices of hydrogels. When the NSAID is naproxen (1), the resultant hydrogelator 1a forms a hydrogel at a critical concentration (cgc) of 0.2 wt % at pH 7.0. Hydrogelator 1a, also acting as a general motif, enables enzymatic hydrogelation in which the precursor turns into a hydrogelator upon hydrolysis catalyzed by a phosphatase at physiological conditions. The conjugates of Phe–Phe with other NSAIDs, such as (R)-flurbiprofen (2), racemic flurbiprofen (3), and racemic ibuprofen (4), are able to form molecular hydrogels, except in the case of aspirin (5). After the conjugation with the small peptides, NSAIDs exhibit improved selectivity to their targets. In addition, the peptides made of D-amino acids help preserve the activities of NSAIDs. Besides demonstrating that common NSAIDs are excellent candidates to promote aromatic–aromatic interaction in water to form hydrogels, this work contributes to the development of functional molecules that have dual or multiple roles and ultimately may lead to new molecular hydrogels of therapeutic agents for topical use.

Effects of small peptides or amino acids infused to a perfused area of the skin of Angora goats on mohair growth

2002 ◽  
Vol 80 (4) ◽  
pp. 1097-1104 ◽  
Author(s):  
R. Puchala ◽  
S. G. Pierzynowski ◽  
T. Wuliji ◽  
A. L. Goetsch ◽  
T. Sahlu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Small Peptides ◽  
Angora Goats

Stereoselective and Site-Specific Allylic Alkylation of Amino Acids and Small Peptides via a Pd/Cu Dual Catalysis

2017 ◽  
Vol 139 (29) ◽  
pp. 9819-9822 ◽  
Author(s):  
Xiaohong Huo ◽  
Rui He ◽  
Jingke Fu ◽  
Jiacheng Zhang ◽  
Guoqiang Yang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Allylic Alkylation ◽  
Small Peptides ◽  
Site Specific ◽  
Dual Catalysis

EXTRACELLULAR ORGANIC NITROGEN IN USTILAGO MAYDIS FERMENTATION BROTHS

1956 ◽  
Vol 34 (1) ◽  
pp. 1195-1198
Author(s):  
Eugene L. Dulaney ◽  
E. Bilinski ◽  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Organic Nitrogen ◽  
Ustilago Maydis ◽  
Ammonia Nitrogen ◽  
Small Peptides ◽  
Lysine Concentration ◽  
High Level ◽  
Fermentation Broths

Free amino acids and small peptides make up most of the extracellular organic nitrogen in media from shaken and aerated Ustilago maydis fermentations. Of the 3.5 mgm./ml. ammonia nitrogen added, 2.9 mgm./ml. remained in the extracellular broth. This extracellular nitrogen contained 1.17 mgm./ml. of organic nitrogen and 1.74 mgm./ml. of residual ammonia nitrogen. At least 53% of extracellular organic nitrogen is in the form of free amino acids. Fifteen amino acids were estimated quantitatively in acid-hydrolyzed broth and a particularly high level of arginine (1.14 mgm./ml.) was found. The amounts of methionine and tryptophan in the broth were quite low but the lysine concentration 0.400 mgm./ml. was relatively high.

scholarly journals The El Tor Biotype of Vibrio cholerae Exhibits a Growth Advantage in the Stationary Phase in Mixed Cultures with the Classical Biotype

2009 ◽  
Vol 192 (4) ◽  
pp. 955-963 ◽  
Author(s):  
Subhra Pradhan ◽  
Amit K. Baidya ◽  
Amalendu Ghosh ◽  
Kalidas Paul ◽  
Rukhsana Chowdhury
Keyword(s):  
Amino Acids ◽  
Stationary Phase ◽  
Vibrio Cholerae ◽  
Competitive Growth ◽  
Small Peptides ◽  
Ileal Loop ◽  
Infant Mouse ◽  
Culture Filtrates ◽  
El Tor

ABSTRACT Vibrio cholerae strains of the O1 serogroup that typically cause epidemic cholera can be classified into two biotypes, classical and El Tor. The El Tor biotype emerged in 1961 and subsequently displaced the classical biotype as a cause of cholera throughout the world. In this study we demonstrate that when strains of the El Tor and classical biotypes were cocultured in standard LB medium, the El Tor strains clearly had a competitive growth advantage over the classical biotype starting from the late stationary phase and could eventually take over the population. The classical biotype produces extracellular protease(s) in the stationary phase, and the amounts of amino acids and small peptides in the late stationary and death phase culture filtrates of the classical biotype were higher than those in the corresponding culture filtrates of the El Tor biotype. The El Tor biotype cells could utilize the amino acids more efficiently than the classical biotype under the alkaline pH of the stationary phase cultures but not in medium buffered to neutral pH. The growth advantage of the El Tor biotype was also observed in vivo using the ligated rabbit ileal loop and infant mouse animal models.

Diversity in growth and protein degradation by dairy relevant lactic acid bacteria species in reconstituted whey

2012 ◽  
Vol 79 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Micaela Pescuma ◽  
Elvira M. Hébert ◽  
Elena Bru ◽  
Graciela Font de Valdez ◽  
Fernanda Mozzi
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Protein Degradation ◽  
Proteolytic Activity ◽  
Starter Culture ◽  
Whey Proteins ◽  
Principal Component ◽  
Fermented Foods ◽  
Small Peptides

The high nutritional value of whey makes it an interesting substrate for the development of fermented foods. The aim of this work was to evaluate the growth and proteolytic activity of sixty-four strains of lactic acid bacteria in whey to further formulate a starter culture for the development of fermented whey-based beverages. Fermentations were performed at 37°C for 24 h in 10 and 16% (w/v) reconstituted whey powder. Cultivable populations, pH, and proteolytic activity (o-phthaldialdehyde test) were determined at 6 and 24 h incubation. Hydrolysis of whey proteins was analysed by Tricine SDS-PAGE. A principal component analysis (PCA) was applied to evaluate the behaviour of strains. Forty-six percent of the strains grew between 1 and 2 Δlog CFU/ml while 19% grew less than 0·9 Δlog CFU/ml in both reconstituted whey solutions. Regarding the proteolytic activity, most of the lactobacilli released amino acids and small peptides during the first 6 h incubation while streptococci consumed the amino acids initially present in whey to sustain growth. Whey proteins were degraded by the studied strains although to different extents. Special attention was paid to the main allergenic whey protein, β-lactoglobulin, which was degraded the most byLactobacillus acidophilusCRL 636 andLb. delbrueckiisubsp.bulgaricusCRL 656. The strain variability observed and the PCA applied in this study allowed selecting appropriate strains able to improve the nutritional characteristics (through amino group release and protein degradation) and storage (decrease in pH) of whey.

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