Diketopiperazine-mediated peptide formation in aqueous solution

Nagayama, Masaharu; Takaoka, Osamu; Inomata, Katsuhiko; Yamagata, Yuki

doi:10.1007/bf01808107

Cited by 56 publications

(37 citation statements)

References 25 publications

(20 reference statements)

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“…This was in agreement with previously reported results, that the formation of peptide bonds of triglycine, tetraglycine or pentaglycine from glycine anhydride and glycine, diglycine or triglycine respectively (glycine anhydride + (glycine) n → (glycine) n+2 ) proceed through the nucleophilic attack of an amino group of the amino acids or the oligoglycines on the glycine anhydride accompanied by the ringopening, thus the larger the number of n, the higher the yield of the resulting peptide 28 . Copolymerization of L-lactide with glycine anhydride was further studied using other catalysts.…”

Section: Resultssupporting

confidence: 93%

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Noomhorm¹,

Tokiwa²

2008

ScienceAsia

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Poly(ester-amide)s were prepared by ring-opening copolymerization of L-lactide with glycine anhydride to form poly(lactide-co-glycine) and with alanine anhydride to form poly(lactide-co-alanine). At 195 o C there were about 5.7 mol% inclusion of glycine using potassium tert-butoxide as catalyst in poly(lactideco-glycine) and 5.0 mol% inclusion of alanine using tin(II) bis-2-ethylhexanoate as catalyst in poly(lactideco-alanine). Enzymatic degradation studies showed that both copolymers could be degraded by proteinase K and glycine and alanine were included in their respective copolymers.

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Section: Resultssupporting

confidence: 93%

Untitled

Noomhorm¹,

Tokiwa²

2008

ScienceAsia

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“…This phenomenon can be attributed to the intramolecular condensation of Ala [34], which proceeded readily because of the short distance between the amino and carboxyl groups of a single Ala molecule. Besides, the stereochemical feasibility of Ala made the intramolecular condensation much more readily [35,36]. It has been reported that the activation energy for the conversion of (Ala) 2 to DKP is significantly lower than that for the formation of (Ala) 2 from two Ala molecules, and the formation of DKP is preferred in most condensation reactions especially at relatively high temperature [37].…”

Section: Resultsmentioning

confidence: 99%

Mechanism of promoted dipeptide formation on hydroxyapatite crystal surfaces

Zhang

et al. 2011

Chin. Sci. Bull.

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The formation of dipeptides from amino acids can be driven by hydroxyapatite at a relatively low temperature in air. For example, the formation of (Ala) 2 from Ala is induced on hydroxyapatite at 110C with considerable yield. Typically, condensing agents, high temperatures (>250C) or high pressures (>25 MPa) are required to drive the condensation of amino acids. Similar effects are observed in the condensation of Gly, Glu and Asp. Experiments demonstrate that hydroxyapatite is an effective inorganic catalytic agent, reducing the activation barrier for the formation of dipeptides by more than 50%. HAP promotes condensation by adsorbing amino acid monomers in an organized manner, which decreases the distance between amino and carboxyl groups on neighboring molecules and extends the contact time of the reaction groups. This work provides a chemical understanding of the primitive condensation of amino acids and reveals a mechanism for enhancement of mineral catalysts. It is important that the conditions used for hydroxyapatite-assisted dipeptide formation are not harsh and can be readily achieved, revealing a possible mechanism for the chemical evolution of biomolecules over geologic ages.

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“…The carbamoylating agent is cyanate, formed from the urea (45). When a similar reaction was run in an open system to facilitate ammonia loss, half of the urea was destroyed after 5 hr at 90°C and pH 7 (46). Diglycine, oligoglycines, and diketopiperazines were other reaction products.…”

Section: ϫ5mentioning

confidence: 99%

Prebiotic cytosine synthesis: A critical analysis and implications for the origin of life

Shapiro

1999

Proc. Natl. Acad. Sci. U.S.A.

158

101

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A number of theories propose that RNA, or an RNA-like substance, played a role in the origin of life. Usually, such hypotheses presume that the Watson-Crick bases were readily available on prebiotic Earth, for spontaneous incorporation into a replicator. Cytosine, however, has not been reported in analyses of meteorites nor is it among the products of electric spark discharge experiments. The reported prebiotic syntheses of cytosine involve the reaction of cyanoacetylene (or its hydrolysis product, cyanoacetaldehyde), with cyanate, cyanogen, or urea. These substances undergo side reactions with common nucleophiles that appear to proceed more rapidly than cytosine formation. To favor cytosine formation, reactant concentrations are required that are implausible in a natural setting. Furthermore, cytosine is consumed by deamination (the half-life for deamination at 25°C is Ϸ340 yr) and other reactions. No reactions have been described thus far that would produce cytosine, even in a specialized local setting, at a rate sufficient to compensate for its decomposition. On the basis of this evidence, it appears quite unlikely that cytosine played a role in the origin of life. Theories that involve replicators that function without the Watson-Crick pairs, or no replicator at all, remain as viable alternatives.

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Diketopiperazine-mediated peptide formation in aqueous solution

Cited by 56 publications

References 25 publications

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Mechanism of promoted dipeptide formation on hydroxyapatite crystal surfaces

Prebiotic cytosine synthesis: A critical analysis and implications for the origin of life

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