Ferris and Orgel (1965)

A couple of weeks back, we discussed the Urey-Miller experiment, where the basic building blocks of life, amino acids, were formed in Early Earth conditions. Continuing with this topic, in a previous paper, Ferris and Orgel discusses the prebiological synthesis of adenine by simple cyanide and ammonia mixtures and/or by irradiation with UV light. As discussed in the current paper, it is determined that the most plausible pathway of adenine synthesis will undergo a photochemical rearrangement by irradiation of the HCN Tetramer (diaminomaleonitrile) to give a more efficient pathway to 4-amino-5-cyanoimidazole, which is essential to synthesize adenine in these specific conditions. 

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7 Responses to “Ferris and Orgel (1965)”

  1. Hunter Burgin Says:

    It’s interesting to think that one of the main building blocks of life (adenine) was created from such a toxic chemical as hydrogen cyanide. However to go one step back, doe Orgel assume that HCN was synthesized in the same manner as that in the Urey-Miller experiment? Also, does this same basic reaction also account for the other four nucleic acids or are they synthesized from adenine after this reaction?

    • Antony Says:

      Adenine is different from the other nucleotides. It is the component of adenosine as in the molecule in AMP and ATP. Adenosine are crucial to all life in a more fundamental way. Currently there is an enzyme that synthesis amp and such. Is this paper suggesting that before that there was a “pool” of adenine available for life to for on?

  2. Porter Marsh Says:

    In the experimental section of the paper it describes adding an ammonia/ethanol solution to a bromomalononitrile/ethanol solution over the course of an hour. Was their method for producing pentacyanopropenide their own or were they using an established method? If it was their own method, why did they combine the two solutions over the course of an hour instead of all at once? What outcome is avoided by the long duration of the addition?

  3. Adam Settimo Says:

    Along the same vein as the Urey-Miller experiment, what was the justification in the parameters selected for this experiment? What I mean is what led them to use conditions such as -80 degrees (C i’m guessing) or reagents such as potassium hydroxide, triethylamine, or morpholine is used in place of ammonia? How did were these conditions relevant to conditions during these early periods? Also, what measures were taken to make sure no outside contamination came into play (like the apparatus for the Urey-Miller experiment), if any?

    They also talk briefly about getting 7 species using thin layer chromatography, but don’t really seem to come back to any explanation about this or am I missing something?

  4. Josh Ellsworth Says:

    Why is it that that diaminomaleonitrile (I) rearranges at 350 (nm I assume) but its isomer 1,1-diamino-2,2-dicyanoethylene rearranges at 253 nm? It seems that in prebiotic conditions both could form, so why do the authors discount the pyrazole rearrangement at 253? What about the mechanism of the rearrangement makes 1,1-diamino-2,2-dicyanoethylene prone to interruption in aqueous solution but allows (I) to proceed to (II)?

  5. Kevin Greenwood Says:

    Though % yields were given, I am interested in some of the side products of this reaction. In a 0.1 M solution, there is plenty of oxygen available for oxidation products to be formed at the wavelengths used in this experiment. A 50-60 % yield is not bad for these reactions; so what makes these products form faster than those that would be seen with addition of an oxygen?

  6. Adam Settimo Says:

    Well, looks like I read the wrong paper again I think. The above note that the paper was from 1965 appears to be a typo. If I’m not wrong, the paper of interest is from 1966 and the 1965 paper by Ferris and Orgel is reference 2.

    My question remains somewhat the same however. The reactions in the paper seem to play fast and loose with the reaction conditions. The researchers go from one set if conditions (Paragraph 2 – Room Temp/ 5 day period) to shortening the reaction time and heating the reaction to get a better yield. Later in the reaction going from I to II the yield is increased by irradiation at room temperature with 350 (nm?) light to about 80% yield.

    What I’m wondering is about the reasoning behind this. With the Urey Miller experiment and the reactions were under the same conditions which makes sense for this primordial soup of reactants. How are the conditions and reactants changing? Shouldn’t they all be subject to the same influences?

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