Glycine is degraded via three pathways. The predominant pathway in animals and plants is the reverse of the glycine synthase pathway. In this context, the enzyme system involved is usually called the glycine cleavage system.
In the second pathway, glycine is degraded in two steps. The first step is the reverse of glycine biosynthesis from serine with serine hydroxymethyl transferase. Serine is then converted to pyruvate by serine dehydratase.
In the third pathway of glycine degradation, glycine is converted to glyoxylate by D-amino acid oxidase. Glyoxylate is then oxidized by hepatic lactate dehydrogenase to oxalate in an NAD+-dependent reaction.
Description source: [Wikipedia](https://en.wikipedia.org/wiki/Glycine#Metabolism).