Nucleic acid notation Nucleic acid notation The nucleic acid notation currently in use was first formalized by the International Union of Pure and Applied Chemistry (IUPAC) in 1970. This universally accepted notation uses the Roman characters G, C, A, and T, to represent the four nucleotides commonly found in deoxyribonucleic acids (DNA). Given the rapidly expanding role for genetic sequencing, synthesis, and analysis in biology, researchers have been compelled to develop alternate notations to further support the analysis and manipulation of genetic data. These notations generally exploit size, shape, and symmetry to accomplish these objectives. Degenerate base symbols in biochemistry are an IUPAC
Prephenic acid Prephenic acid Prephenic acid, commonly also known by its anionic form prephenate, is an intermediate in the biosynthesis of the aromatic amino acids phenylalanine and tyrosine, as well as of a large number of secondary metabolites of the shikimate pathway. It is biosynthesized by a [3,3]-sigmatropic Claisen rearrangement of chorismate. Prephenic acid is an example of achiral (optically inactive) molecule which has two pseudoasymmetric atoms ("i.e." stereogenic but not chirotopic centers), the C1 and the C4 cyclohexadiene ring atoms. It has been shown that of the two possible diastereoisomers, the natural prephenic acid is one that has both substituents at