L-serine (Ser) (Ser)

Serine is a non-essential amino acid that exists in two enantiomers, L-serine and D-serine, both of which are critical for human physiology. L-serine serves as a fundamental building block for protein synthesis and a precursor for essential metabolites, including glycine, cysteine, and sphingolipids (PubChem CID 5951). D-serine, synthesized from L-serine by the enzyme serine racemase, acts as an obligatory co-agonist at the glycine-binding site of the N-methyl-D-aspartate (NMDA) receptor, playing a vital role in excitatory neurotransmission, synaptic plasticity, and memory (NIH/NCBI). While serine itself is a metabolite and not a classical therapeutic protein target like an enzyme or receptor, its metabolic pathways are highly relevant in medicine. L-serine supplementation is currently being investigated as a therapy for neurodegenerative conditions such as Amyotrophic Lateral Sclerosis (ALS) and Hereditary Sensory and Autonomic Neuropathy type 1 (HSAN1), where it may mitigate the production of neurotoxic deoxysphingolipids (PubMed). Furthermore, the upregulation of serine biosynthesis is a hallmark of certain cancers, which rely on the pathway to support rapid cellular proliferation, making the enzymes involved in its synthesis potential targets for oncology (Nature Reviews Cancer).

Other names

(2S)-2-amino-3-hydroxypropanoic acidL-Ser2-amino-3-hydroxypropionic acidS-serine

As a metabolite, L-serine acts as a substrate for protein and lipid synthesis; the D-enantiomer acts as a mandatory co-agonist for the NMDA receptor glycine site.