Generic acid-base catalysis

If we consider the more generic Bronstedt s definition of a base and acid, protons and hydroxide ions do not have specific properties in comparison to other bases. For example, with an acid.4H and its conjngated base , with generic acid-base catalysis, the apparent rate coefficient will have the form  

To determine whether catalysis is specific or generic, we undertake catalysis in the presence of a buffer solution, adjusting the pH of the solution according to the Henderson s equation  

The pH is fixed and the experiment is carried out using different concentrations of. 4H and A respecting the ratio in [ 13.13]. We then have two cases  

In the latter case, we wish to determine the different rate coefficients ko, kAu, kn, koR and kA. 

Mechanisms like the Herzfeld type can account for the different types of generic acid-base catalysis that are possible. For exanqjle, in the case of acid catalysis by an acidv4H during the hydrolysis product SH leading to an isomer P  

---

The term nucleotide is used generically for both RNA and DNA units. The absence of a 2 -OH group in DNA prevents alkali-mediated cleavage of the 3 -5 phosphodiester cleavage observed in RNA and thus makes DNA more resistant to hydrolysis. Both RNA and DNA contain two types of purines, adenine (A) and guanine (G), and two types of pyrimidine bases (Fig. 1C). The second key difference between RNA and DNA is that while cytosine (C) is present in both RNA and DNA, RNA normally contains uracil (U), while DNA contains 5-methyluracil, called thymine (T), as the other pyrimidine base. The difference in chemical structure is reflected in the intrinsic chemical stability of these nucleic acids. The purine N-glycosyl bond in DNA is more unstable than in RNA, and as a result, purines are released much more easily from DNA by acid catalysis. Furthermore, cytosine deamination to produce U also occurs at a finite rate in DNA. 

---