[2] In this case the methyl group derived from the catabolism of glycine can be transferred to other key molecules such as purines and methionine.

The ammonia generated by the glycine cleavage system, is assimilated by the Glutamine synthetase-Glutamine oxoglutarate aminotransferase cycle but costs the cell one ATP and one NADPH.

[3] The glycine cleavage system is constantly present in the leaves of plants, but in small amounts until they are exposed to light.

Initial research using carbon labeling showed decreased levels of CO2 and serine production in the liver, pointing directly to deficiencies glycine cleavage reaction.

[11] Further research has shown that deletions and mutations in the 5' region of the P-protein are the major genetic causes of nonketotic hyperglycinemia.

This specific mutation directly affected the active site of the T-protein, causing lowered efficiency of the glycine cleavage system.