Purification and chemical characterization of beta-trace protein from human cerebrospinal fluid: its identification as prostaglandin D synthase

J Neurochem. 1993 Aug;61(2):451-6. doi: 10.1111/j.1471-4159.1993.tb02145.x.


beta-Trace protein from pooled human CSF was purified to homogeneity. An apparent molecular mass of 23-29 kDa was determined for the polypeptide on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Amino-terminal sequencing of the polypeptide yielded the unique amino acid sequence APEAQVSVQPNFQQDKFLGRWFSA. Alignment of amino acid sequences obtained from tryptic peptides with the sequence previously deduced from a cDNA clone isolated by other investigators allowed the identification of beta-trace protein as prostaglandin D synthase [prostaglandin-H2 D-isomerase; (5Z, 13E)-(15S)-9 alpha, 11 alpha-epidioxy-15-hydroxyprosta-5,13-dienoate D-isomerase; EC]. A conservative amino acid exchange (Thr instead of Ser) was detected at amino acid position 154 of the beta-trace polypeptide chain in the corresponding tryptic peptide. The two N-glycosylation sites of the polypeptide were shown to be almost quantitatively occupied by carbohydrate. Carbohydrate compositional as well as methylation analysis indicated that Asn29 and Asn56 bear exclusively complex-type oligosaccharide structures (partially sialylated with alpha 2-3- and/or alpha 2-6-linked N-acetylneuraminic acid) that are almost quantitatively alpha 1-6 fucosylated at the proximal N-acetylglucosamine; approximately 70% of these molecules contain a bisecting N-acetylglucosamine. Agalacto structures as well as those with a peripheral fucose are also present.

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Electrophoresis, Polyacrylamide Gel
  • Glycosylation
  • Humans
  • Intramolecular Oxidoreductases*
  • Isomerases / cerebrospinal fluid*
  • Isomerases / chemistry
  • Lipocalins
  • Methylation
  • Molecular Sequence Data
  • Molecular Weight
  • Peptide Fragments / chemistry
  • Peptide Fragments / metabolism
  • Peptide Mapping
  • Protein Processing, Post-Translational
  • Trypsin / metabolism


  • Lipocalins
  • Peptide Fragments
  • Trypsin
  • Isomerases
  • Intramolecular Oxidoreductases
  • prostaglandin R2 D-isomerase