Send to

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 1993 Nov 1;90(21):10265-9.

Ceramide UDPgalactosyltransferase from myelinating rat brain: purification, cloning, and expression.

Author information

Institute of Biochemistry, Medical Faculty of the University of Cologne, Germany.


Cerebrosides and sulfatides are major glycosphingolipids of the lipid bilayer of the myelin sheath assembled by oligodendrocytes and Schwann cells during myelination. Cerebrosides are synthesized by ceramide UDPgalactosyltransferase [CGT; 2-hydroxyacylsphinogosine 1-beta-galactosyl-transferase; UDPgalactose:2-(2-hydroxyacyl)sphingosine 1-beta-D-galactosyltransferase; UDPgalactose:2-(2-hydroxyacyl)sphingosine 1-beta-D-galactosyltransferase, EC] with UDPgalactose and ceramide as substrates. Here we describe a purification method from microsomes of myelinating rat brains that includes ion exchange, dye ligand, and lectin affinity chromatography. The enzyme was identified as a 64-kDa high-mannose glycoprotein. A CGT-specific cDNA clone was isolated from a rat brain cDNA library using CGT oligonucleotides derived from peptide sequences. The cDNA insert encodes a polypeptide of 541 amino acid residues with a molecular weight of 61,126. The polypeptide has three putative glycosylation sites and one hydrophobic domain at the C terminus. A 20-residue N-terminal signal sequence is lost during cotranslational translocation. Northern blot analysis demonstrates that CGT expression is restricted to brain tissue and is time dependent, correlating with myelin basic protein expression. In situ hybridization reveals that CGT expression is restricted to the oligodendrocyte-containing cell layers of cerebrum and cerebellum, which also express myelin basic protein. The amino acid sequence of CGT shows significant homology to mammalian UDPglucuronyltransferases, which suggests a common evolutionary origin of these enzymes.

[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center