So this basically comes from folic acid, our tetrahydrophobate. Now, the enzyme that catalyzed this step is methionine synthase, and it uses vitamin B twelve. And vitamin B twelve is also known as Kobalamine. So this is one of the few enzymes inside our body that actually utilizes vitamin B twelve. The other enzyme we're going to talk about at the end. So this is our cycle that allows us to basically, number one, regenerate the methionine while forming that stem, and also regenerating the THF that can be used in various processes within our body.