scholarly journals Synthesis of Organic Molecules, R Ribose and S Amino Acids by Adsorption on Carbon at The Birth of Life on The Earth

2016 ◽  
Vol 12 (30) ◽  
pp. 1
Author(s):  
Vladimir Zhmakin
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Phosphoric Acid ◽  
Organic Molecules ◽  
Optical Purity ◽  
Optically Active ◽  
Volcanic Gas ◽  
Early Atmosphere ◽  
The Earth

Reasons for appearance of optically active organic molecules in nature have not been ascertained up to the present, but clarification of conditions on the Earth during the period of their appearance can contribute to this. H2 and gases, containing H2, were oxidized by CO2 with allocation of carbon and H2O or CH2O and СНO(OН) in volcanic gas and in the early atmosphere. During adsorption on carbon CH2O dissolved in water could be the synthesis only of R (rectus, Latin) ribose, and with NH3 and СНO(OН) synthesis of glycine and only of S (sinister) serine, and on its bases of other S amino acids. Adsorption on the carbon ensured in complex: concentration of initial components, hydrophobic-hydrophilic properties, optical purity, protection from hydration, decay and racemization. It is shown the possibility of the early Archean reactions: dehydration of phosphoric acid, of phosphoester bonds connection formation in nucleotides, with CH2O fatty acids and nitrogenous bases.

scholarly journals Astrochemistry as the basics of Astrobiology: from simplest molecules to bioindicatorsonexoplanets surfaces

2018 ◽  
Vol 2 (1) ◽  
pp. 33-64
Author(s):  
A.G. Yeghikyan ◽  
Keyword(s):  
Amino Acids ◽  
Origin Of Life ◽  
Biological Evolution ◽  
Complex Compounds ◽  
Optically Active ◽  
Point Of View ◽  
Heavy Hydrocarbons ◽  
The Earth ◽  
Other Substances ◽  
The Origin Of Life

The problem of the origin of Life is discussed from the astrophysical point of view. Most biologists and geologists up to the present time believe that Life was originated on the Earth in some initial natural chemical pre-reactors, where a mixture of water, ammonia, methane containing species and some other substances, under the influence of an energy source like, e.g. lightning, turned into quite complex compounds such as amino acids and complex hydrocarbons. In fact, under conditions of the primordial Earth, it is not possible to obtain such pre-biological molecules by not-bio-chemical methods, as discussed in this paper. Instead, an astrophysical view of the problem of the origin of Life on the Earth is proposed and it is recalled that the biological evolution on the Earth was preceded by the chemical evolution of complex chemical compounds, mostly under extraterrestrial conditions, where it is only possible to form optically active amino acids, sugars and heavy hydrocarbons necessary for constructing the first pre-biomolecules. Then, according to a widespread point of view, they were brought to Earth by comets and dust between 4.5 and 3.8 billion years ago. Some part of the matter of comets landed unchanged during grazing collisions. Prebiotic complexes on the surface of the planet participate in the formation of a specific cover with a reflective spectrum (or color index), whose characteristic details can be tried to reveal by observation. The most promising bio-indicators at present are optically active amino acids and their derivatives, however, the existing observational capabilities are insufficient to identify them. More promising as (pre)biomarkers are the heavy hydrocarbons discussed in this article, in particular bitumen and isoprene hydrocarbons.

Asymmetric syntheses of optically active α-amino acids by hydrocyanic acid addition to the optically active Schiff base

1970 ◽  
Vol 48 (12) ◽  
pp. 1881-1884 ◽  
Author(s):  
Mahendra S. Patel ◽  
Michael Worsley
Keyword(s):  
Amino Acids ◽  
Schiff Base ◽  
Optical Purity ◽  
Optically Active ◽  
Hydrocyanic Acid ◽  
Asymmetric Syntheses ◽  
Acid Addition

The syntheses of L(+) and D(−) enantiomers of α-amino acids, norvaline, norleucine, and leucine, as their hydrochloride salts have been achieved in almost 100% optical purity and 40–60% overall yield.

scholarly journals Prebiotic materials from on and off the early Earth

2006 ◽  
Vol 361 (1474) ◽  
pp. 1689-1702 ◽  
Author(s):  
Max Bernstein
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Oxidation State ◽  
Hydrothermal Vents ◽  
Organic Molecules ◽  
Early Earth ◽  
The Earth ◽  
Evolution Of Life ◽  
Carbon Compounds ◽  
Compare And Contrast

One of the greatest puzzles of all time is how did life arise? It has been universally presumed that life arose in a soup rich in carbon compounds, but from where did these organic molecules come? In this article, I will review proposed terrestrial sources of prebiotic organic molecules, such as Miller–Urey synthesis (including how they would depend on the oxidation state of the atmosphere) and hydrothermal vents and also input from space. While the former is perhaps better known and more commonly taught in school, we now know that comet and asteroid dust deliver tons of organics to the Earth every day, therefore this flux of reduced carbon from space probably also played a role in making the Earth habitable. We will compare and contrast the types and abundances of organics from on and off the Earth given standard assumptions. Perhaps each process provided specific compounds (amino acids, sugars, amphiphiles) that were directly related to the origin or early evolution of life. In any case, whether planetary, nebular or interstellar, we will consider how one might attempt to distinguish between abiotic organic molecules from actual signs of life as part of a robotic search for life in the Solar System.

1010-P: Effects of MEDI0382, an Oxyntomodulin-Like Peptide with Targeted GLP-1/Glucagon Receptor Activity, on Amino Acids, Ketones, and Free Fatty Acids

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 1010-P
Author(s):  
VICTORIA E. PARKER ◽  
DARREN ROBERTSON ◽  
TAO WANG ◽  
DAVID C. HORNIGOLD ◽  
MAXIMILIAN G. POSCH ◽  
...  
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Free Fatty Acids ◽  
Receptor Activity ◽  
Glucagon Receptor

Gastrointestinal Interaction between Dietary Amino Acids and Gut Microbiota: With Special Emphasis on Host Nutrition

2020 ◽  
Vol 21 (8) ◽  
pp. 785-798 ◽  
Author(s):  
Abedin Abdallah ◽  
Evera Elemba ◽  
Qingzhen Zhong ◽  
Zewei Sun
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Immune System ◽  
Gut Microbiota ◽  
Short Chain Fatty Acids ◽  
Nutrition And Health ◽  
Nitrogenous Compounds ◽  
Dietary Amino Acids ◽  
Host Nutrition ◽  
Chain Fatty Acids

The gastrointestinal tract (GIT) of humans and animals is host to a complex community of different microorganisms whose activities significantly influence host nutrition and health through enhanced metabolic capabilities, protection against pathogens, and regulation of the gastrointestinal development and immune system. New molecular technologies and concepts have revealed distinct interactions between the gut microbiota and dietary amino acids (AAs) especially in relation to AA metabolism and utilization in resident bacteria in the digestive tract, and these interactions may play significant roles in host nutrition and health as well as the efficiency of dietary AA supplementation. After the protein is digested and AAs and peptides are absorbed in the small intestine, significant levels of endogenous and exogenous nitrogenous compounds enter the large intestine through the ileocaecal junction. Once they move in the colonic lumen, these compounds are not markedly absorbed by the large intestinal mucosa, but undergo intense proteolysis by colonic microbiota leading to the release of peptides and AAs and result in the production of numerous bacterial metabolites such as ammonia, amines, short-chain fatty acids (SCFAs), branched-chain fatty acids (BCFAs), hydrogen sulfide, organic acids, and phenols. These metabolites influence various signaling pathways in epithelial cells, regulate the mucosal immune system in the host, and modulate gene expression of bacteria which results in the synthesis of enzymes associated with AA metabolism. This review aims to summarize the current literature relating to how the interactions between dietary amino acids and gut microbiota may promote host nutrition and health.

scholarly journals Peculiarities of promiscuous l-threonine transaldolases for enantioselective synthesis of β-hydroxy-α-amino acids

2021 ◽  
Author(s):  
Shan Wang ◽  
Hai Deng
Keyword(s):  
Amino Acids ◽  
Organic Molecules ◽  
Stereoselective Synthesis ◽  
Enantioselective Synthesis ◽  
General Mechanism ◽  
Future Developments ◽  
Key Points ◽  
Biomaterial Science ◽  
One Step ◽  
Harsh Conditions

Abstract The introduction of β-hydroxy-α-amino acids (βHAAs) into organic molecules has received considerable attention as these molecules have often found widespread applications in bioorganic chemistry, medicinal chemistry and biomaterial science. Despite innovation of asymmetric synthesis of βHAAs, stereoselective synthesis to control the two chiral centres at Cα and Cβ positions is still challenging, with poor atomic economy and multi protection and deprotection steps. These syntheses are often operated under harsh conditions. Therefore, a biotransformation approach using biocatalysts is needed to selectively introduce these two chiral centres into structurally diverse molecules. Yet, there are few ways that enable one-step synthesis of βHAAs. One is to extend the substrate scope of the existing enzyme inventory. Threonine aldolases have been explored to produce βHAAs. However, the enzymes have poor controlled installation at Cβ position, often resulting in a mixture of diastereoisomers which are difficult to be separated. In this respect, l-threonine transaldolases (LTTAs) offer an excellent potential as the enzymes often provide controlled stereochemistry at Cα and Cβ positions. Another is to mine LTTA homologues and engineer the enzymes using directed evolution with the aim of finding engineered biocatalysts to accept broad substrates with enhanced conversion and stereoselectivity. Here, we review the development of LTTAs that incorporate various aldehyde acceptors to generate structurally diverse βHAAs and highlight areas for future developments. Key points • The general mechanism of the transaldolation reaction catalysed by LTTAs • Recent advances in LTTAs from different biosynthetic pathways • Applications of LTTAs as biocatalysts for production of βHAAs

scholarly journals Formation of Thiophene under Simulated Volcanic Hydrothermal Conditions on Earth—Implications for Early Life on Extraterrestrial Planets?

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 149
Author(s):  
Thomas Geisberger ◽  
Jessica Sobotta ◽  
Wolfgang Eisenreich ◽  
Claudia Huber
Keyword(s):  
Fatty Acids ◽  
Hydrogen Sulfide ◽  
Early Life ◽  
Organic Molecules ◽  
Metal Sulfides ◽  
Early Earth ◽  
Hydrothermal Conditions ◽  
Evolution Of Metabolism ◽  
Thiophene Derivatives ◽  
The Origin Of Life

Thiophene was detected on Mars during the Curiosity mission in 2018. The compound was even suggested as a biomarker due to its possible origin from diagenesis or pyrolysis of biological material. In the laboratory, thiophene can be synthesized at 400 °C by reacting acetylene and hydrogen sulfide on alumina. We here show that thiophene and thiophene derivatives are also formed abiotically from acetylene and transition metal sulfides such as NiS, CoS and FeS under simulated volcanic, hydrothermal conditions on Early Earth. Exactly the same conditions were reported earlier to have yielded a plethora of organic molecules including fatty acids and other components of extant metabolism. It is therefore tempting to suggest that thiophenes from abiotic formation could indicate sites and conditions well-suited for the evolution of metabolism and potentially for the origin-of-life on extraterrestrial planets.

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