Chapter 25, Problem 25.15P

Interpretation Introduction

(a)

Interpretation:

A curved arrow mechanism for the biosynthesis of S-adenosylmethionine in which the amino acid methionine undergoes an enzyme-catalyzed reaction with ATP to give SAM and triphosphate, assuming it is an ${\mathrm{S}}_{\mathrm{N}}2\mathrm{ }$ process is to be drawn.

Concept Introduction:

${\mathrm{S}}_{\mathrm{N}}2$ reaction mechanism is a one step process. The nucleophile attacks the substrate from the backside, and the leaving group departs from the opposite side, simultaneously.

Interpretation Introduction

(b)

Interpretation:

The role of $\mathrm{M}{\mathrm{g}}^{2+}$ ions in the catalytic process is to be explained.

Concept Introduction:

A species which stabilizes the products of a reaction is useful by neutralizing the charge.