Degradation of Methionine to ATP

I've never seen this biochemical pathway before, that's really cool. After searching a little bit, I found this diagram that could help. As you see, there is adenosine mentioned, which is an integral part of ATP. Although mammals cannot synthesize methionine, they can still use it in a variety of biochemical pathways, like the one you mentioned.



Methionine is converted to S-adenosylmethionine (SAM) by (1) methionine adenosyltransferase. SAM serves as a methyl-donor in many (2) methyltransferase reactions, and is converted to S-adenosylhomocysteine (SAH). (3) Adenosylhomocysteinase converts SAH to homocysteine.

Here's another simplified look of it: