Reaction: PXLP-K56-SRR dimer deaminates L-Ser

- in pathway: Serine biosynthesis
N-methyl D-aspartate (NMDA) receptors play a key role in excitatory neurotransmission, learning, memory and synaptic plasticity. Their activity is modulated by the agonist glutamate and by the co-agonists D-Serine (D-Ser) and glycine (gly). In human brain, dimeric serine racemase (SRR), a pyridoxal 5'-phosphate-dependent enzyme (Smith et al. 2010), is a bifunctional enzyme mediating mainly L-Serine catabolism by alpha,beta-elimination of water to form pyruvate (De Miranda et al. 2002, Foltyn et al. 2005). Part of L-Serine is not deaminated then SRR can also catalyse the isomerisation of L-Ser to D-Ser although this is very much a minor reaction. Thus, D-Ser homeostasis in neurons is modulated by SRR, and therefore indirectly, modulates NMDA receptors. Targeting SRR could find potential in neurodegenerative diseases (Canu et al. 2014). Mg2+ and ATP stimulate SRR (De Miranda et al. 2002).
Reaction - small molecule participants:
H2O [cytosol]
NH3 [cytosol]
PYR [cytosol]
L-Ser [cytosol]
Reactome.org reaction link: R-HSA-9034539

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Reaction input - small molecules:
L-serine zwitterion
ChEBI:33384
Reaction output - small molecules:
water
ChEBI:15377
ammonia
ChEBI:16134
pyruvate
ChEBI:15361
Reactome.org link: R-HSA-9034539