The condensation of nucleo-bases adenine or guanine with sugar ribose gives only minute amounts of nucleosides with correct stereochemistry, and synthesis of pyrimidine nucleosides is even more difficult.
Shapiro (1995, 1999) addressed difficulties in prebiotic syntheses of nucleo- bases adenine and cytosine.
With widely diffused minerals and metal oxides as catalysts, formamide affords all the precursor nucleic bases: purine, adenine, hypoxanthine (bioisomer of guanine), cytosine, uracil and thymine.
Purines and pyrimidines, including adenine, guanine, cytosine, thymine and uracil, play a major role in terrestrial biochemistry.
Thymidine was the most common nucleotide in position 2 and adenine the most abundant nucleotide in the seventh position.
The point mutations at codon-46 and codon-108 represent transitional pyrimidine (thymine to cytosine) and purine (guanine to adenine) substitutions respectively.
Our survey of some obvious candidates singled out adenine mononucleotide as a promising small molecule.
Imaging of intrinsic indicators within tissue, such as nicotinamide adenine dinucleotide, retinol, indoleamines, and collagen provided crucial physiological information.
