L-Serine is needed in human brain in large amounts as precursor to important biomolecules such as nucleotides, phospholipids and the neurotransmitters glycine and D-serine. The pathway for its synthesis starts with 3-phosphoglycerate and it later needs glutamate as an amination agent. Deficiencies in the participating enzymes lead to severe neurological symptoms that are treatable with serine if treatment starts early (de Koning & Klomp 2004).
