In this article we will discuss about the activation of amino acids and formation of aminoacyl-tRNA. The first step of protein biosynthesis comprises two reactions (see fig. 6-43) catalyzed, for a given amino acid, by one and the same enzyme called activation enzyme, or aminoacyl-tRNA synthetase, or aminoacyl-tRNA ligase. In a first step, the L-amino acid is activated by ATP [...]
The synthesis of nucleic acids (DNAs and RNAs) from nucleosides-5'- triphosphates is characterized by the necessity of conserving the genetic information intact. The DNA is indeed the carrier of this information which is transmitted from generation to generation; this notion is now well established, but it was long believed that this information was carried by proteins. It would therefore be [...]
In this article we will discuss about the process of biosynthesis of nucleic acids. Biosynthesis of Nucleosides-5'-Triphosphates: Among animals, some amino acids cannot be synthesized and must therefore be supplied through diet (essential amino acids). On the contrary, purine and pyrimidine nucleotides can be synthesized "de novo", from precursors like CO2, NH3, formiate, glycine etc., and this is true of [...]