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Biochemistry. 1984 Jul 31;23(16):3784-8.

Identification and characterization of N-acetyl-2,3-didehydro-2-deoxyneuraminic acid as a metabolite in mammalian brain.

Abstract

We have identified N-acetyl-2,3-didehydro-2-deoxyneuraminic acid (NADNA) in bovine and in rat brain. Identification was made by mass spectrometric and gas-liquid chromatographic analysis of the per(trimethylsilyl) derivative of the purified brain compound. Central nervous system NADNA hitherto has escaped detection; it behaves chromogenically and chromatographically during purification on ion-exchange chromatography as free N-acetylneuraminic acid (NANA) that also occurs in brain. Although NADNA is a dehydro analogue of NANA, we have ascertained that brain NANA does not give rise to NADNA as an artifact during its purification from brain. Three hours after intracranial injection of [14C]-N-acetylmannosamine [( 14C]ManNAc), we detected [14C]NANA but no [14C]NADNA in rat brain. ManNAc is a brain NANA precursor, and at this time, formation of cytidine 5'-phosphate (CMP)-[14C]NANA from [14C]ManNAc is at a maximum. This finding precludes decomposition of CMP-NANA as a source of brain NADNA. Upon intracranial injection of [14C]ManNAc, [14C]NADNA became detectable at 19 h and reached a maximum level around 40 h later; this maximum of labeling of NADNA coincides with the maximum label in brain sialo conjugate-NANA. These findings clearly demonstrate the occurrence of NADNA in mammalian brain. From the evidence, NADNA may derive enzymatically from brain sialo conjugates.

PMID:
6477896
DOI:
10.1021/bi00311a034
[Indexed for MEDLINE]

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