Abstract:
:High levels of D-serine occur in mammalian brain, where it appears to be an endogenous ligand of the glycine site of N-methyl-D-aspartate receptors. In glial cultures of rat cerebral cortex, D-serine is enriched in type II astrocytes and is released upon stimulation with agonists of non-N-methyl-D-aspartate glutamate receptors. The high levels of D-serine in discrete areas of rat brain imply the existence of a biosynthetic pathway. We have purified from rat brain a soluble enzyme that catalyzes the direct racemization of L-serine to D-serine. Purified serine racemase has a molecular mass of 37 kDa and requires pyridoxal 5'-phosphate for its activity. The enzyme is highly selective toward L-serine, failing to racemize any other amino acid tested. Properties such as pH optimum, Km values, and the requirement for pyridoxal phosphate resemble those of bacterial racemases, suggesting that the biosynthetic pathway for D-amino acids is conserved from bacteria to mammalian brain.
journal_name
Proc Natl Acad Sci U S Aauthors
Wolosker H,Sheth KN,Takahashi M,Mothet JP,Brady RO Jr,Ferris CD,Snyder SHdoi
10.1073/pnas.96.2.721subject
Has Abstractpub_date
1999-01-19 00:00:00pages
721-5issue
2eissn
0027-8424issn
1091-6490journal_volume
96pub_type
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