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 [...]
In this article we will discuss about the formation of purine and pyrimidine deoxyribonucleosies. Formation of Purine Deoxyribonucleosides-5'- Triphosphates: The deoxyribonucleotides are simply formed by reduction of the corresponding ribonucleotides. Thus reduction of carbon 2' of ribose, takes place in E.coli and animal tissues at the ribonucleosides-5'-diphosphates stage, at the cost of a protein of low molecular weight, thioredoxin, comprising [...]
The biosynthesis of the DNA must consist in a replication or duplication. The study of the DNA structure as proposed by Crick and Watson (see fig. 6-15) gives an idea of the mechanism of this replication. Each nucleotide of the template DNA chain need only be recognized by a complementary nucleotide before the latter is incorporated at the end of [...]