Linked Life Data

12227431

Source:http://linkedlifedata.com/resource/pubmed/id/12227431

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2002-9-13
pubmed:abstractText
The claim by Nelson et al. (2001) that the reaction of cyanoacetaldehyde and urea provides 'an efficient prebiotic synthesis' of cytosine is disputed. The authors have not dealt with the important points presented in a criticism of this reaction (Shapiro, 1999): (1) The reactants undergo side reactions with common nucleophiles that appear to proceed more rapidly than cytosine formation, and (2) No reactions have been described thus far that would produce cytosine at a rate sufficient to compensate for its decomposition by deamination, and permit accumulation over extended periods of time. Instead, Nelson et al. have conducted 'drying-down' experiments, in an effort to simulate evaporations on the early Earth, but the design of these experiments is flawed. The initial reactant concentrations are much higher than might be expected in a natural setting, and potentially interfering substances such as glycine, cyanide and thiols have been excluded. 'Drying beaches and drying lagoons' have been invoked as sites for such a reaction but no effort has been made to describe the characteristics of such sites or to estimate their frequency with reference to the present Earth. In the absence of contradictory data, the conclusion put forward in Shapiro (1999) remains valid: 'It was quite unlikely that cytosine played a role in the origin of life'.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0169-6149
pubmed:author
pubmed:issnType
Print
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
275-8
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Comments on 'concentration by evaporation and the prebiotic synthesis of cytosine'.
pubmed:affiliation
Department of Chemistry, New York University, NY 10003-6688, USA. rs2@nyu.edu
pubmed:publicationType
Journal Article, Comment