Clays and Clay Minerals, Vol. 55, No. 6, 599–605, 2007.
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Authors
Hashizume, Hideo
Theng, Benny K. G.
Issue Date
2007
Type
Article
Language
Keywords
Periodicals , Geology , Adenine , Adenosine , Allophane , 5’-AMP , Adsorption , Ribose
Alternative Title
Adenine, Adenosine, Ribose And 5’-amp Adsorption To Allophane
Abstract
We have investigated the adsorption of adenine, adenosine, ribose, and adenosine-5’-phosphate (5’-AMP) by allophane at pH 4, 6 and 8. Adenine, adenosine and ribose gave similar isotherms, i.e. adsorption increased regularly with solution concentration and decreased in the order: pH 8 > pH 6 > pH 4. Allophane had a greater affinity for 5’-AMP than for adenine, adenosine or ribose. Further, the extent of adsorption for 5’-AMP increased in the order: pH 8 << pH 6&pH 4. The adsorption of 5’-AMP at pH 4 and pH 6 was about 60 times greater than at pH 8. The strong adsorption of 5’-AMP accords with the well known high phosphate-retention capacity of allophane and allophane-rich soils. The experimental data may be rationalized in terms of the pH-dependent charge characteristics of the organic solutes and allophane. The large propensity of allophane to retain 5’-AMP is ascribed to ligand exchange between the phosphate of 5’-AMP and the hydroxylof (HO)Al(OH2) groups, exposed at perforations on the wall of allophane spherules, giving rise to a surface (chelation) complex. The high affinity of nucleotides for allophane has implications for the possible role of allophane in the abiotic formation of RNA-type polynucleotides although nucleotide ‘immobilization’ by surface complexation might hinder RNA oligomerization.
Description
Clays and Clay Minerals, Vol. 55, No. 6, 599–605, 2007. Hideo Hashizume; Benny K. G. Theng. Adenine, Adenosine, Ribose And 5’-amp Adsorption To Allophane. DOI: 10.1346/CCMN.2007.0550607. Copyright © 2007, The Clay Minerals Society
Citation
Clays and Clay Minerals, Vol. 55, No. 6, 599–605, 2007.
Publisher
The Clay Minerals Society
License
Copyright © 2006-2018, The Clay Minerals Society