Question

REVIEW INSIGHT Hмт RHNOC ON NH NO но он но он Lysine peptide S-adenosylmethionine Methyllysine peptide S-adenosy homocysteine substrate product Figure 1 Mechanism of lysine methylation catalysed by histone lysine methyltransferases. The lysine amino group of the substrate histone polypeptide engages in an SN 2 reaction with the activated co-factor S-adenosylmethionine (SAM), resulting in the formation of an N-methylated lysine and S-adenosy homocysteine (SAH).

Label:

-nucleophile

-electrophile

-leaving group

Draw a reasonable, step by step arrow pushing mechanism for the overall reaction. You may abbreviate non-involved parts of any of the molecules with 'R' groups, and you can assume that water is present in the reaction (to act as either an acid or a base).

Answer 1

In the last step of deprotonation , use H2O in place of HMTs and it will act as a base and abstract acidic hydrogen from nitrogen. I have marked entire molecule to be nucleophile or electrophile because entire molecule is supposed to be nucleophile or electrophile not a single atom. A single atom can be nucleophilic or electrophilic centers and within a molecule there can be more than one nucleophilic or electrophilic centers.

cost Leaving group. RHNOC NH > Product. Nucleophile electrophile Mechanism :- Step! CO₂H RANOC HCV SNR & NH. A 04 0! HO Cost RANOC Product RHNOC Step 2: Deprotonation: RANOG NH NH O (Product)

Thanks