Lysine is recognized as an amino acid obligatory as a building block for all proteins in your body.

The exception to the rule is the DOT1 family, members of which methylate K79 in the globular area of histone H3 and which are structurally not related to SET-domain proteins 4 - 6 Latest work means that SET-area-containing proteins methylate just a few proteins along with histones (see later)