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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 3 (1974), S. 49-56 
    ISSN: 1432-1432
    Keywords: Asymmetric Polymerization ; Origin of Optical Activity ; Kaolin ; Aspartic Acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two recent reports in the literature claim thatl-aspartic acid polymerizes significantly faster thand-aspartic acid in the presence of kaolin in aqueous solution at 90°. The novelty of these observations and their potential significance for molecular evolution and the origin of optical activity in nature has prompted us to attempt a duplication of the experiments involved—using, however, analytical criteria which we felt would be more reliable than those previously employed. In our experimentsl- andd,l-aspartic acid in 0.01M solution were incubated with kaolin at 90° for 8 days. Careful examination of the aqueous residues from such experiments, however, failed to demonstrate any preferential polymerization ofl- overd-aspartic acid under the influence of kaolin, or indeed any significant gross polymerization of aspartic acid at all.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 11 (1978), S. 95-99 
    ISSN: 1432-1432
    Keywords: Radiolysis ; Radioracemization ; Origin of Optical Activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An investigation has been undertaken to determine whether ionizing radiation might engender racemization of optically active amino acids, along with their usual radiolysis. As prototypes, crystalline D- and L-leucine, as well as aqueous solutions of their sodium salts were exposed to the radiation from a 3000 Ci60Coγ-ray source.γ-ray doses which caused about 68% radiolysis of solid leucine left a residue which was about 5% racemized, while racemization proved even greater at lower doses for the dissolved sodium salts. In aqueous solution both percent degradation and percent racemization of the sodium salts were proportional toγ-ray dosage within the range employed (1−27 · 106 rads). Implications of these observations for the origin of molecular asymmetry by theβ-decay parity violation mechanism are discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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