Breakdown of Choline via the Methylation Cycle

https://de.wikibooks.org/wiki/Biochemie_und_Pathobiochemie:_Druckversion#Biosynthese_von_Betain_und_Abbau_zu_Glycin

 

Formaldehyde Breakdown and Reaction to Formyl-THF

Formaldehyde is produced from methanol (the non-drinking alcohol that is toxic) and in small amounts from the breakdown of choline and in other processes like the cholesterol biosynthesis.

10-formyl-THF is a cofactor in the purine synthesis (GMP, AMP).

https://de.wikibooks.org/wiki/Biochemie_und_Pathobiochemie:_Alkohol-Stoffwechsel#Verstoffwechselung_von_Methanol