On 21 Jun 1995, Iain Wilson wrote:
> Posted on behalf of Prof. Niegl Jenkins:
>> *********************************************************
> Does anyone know details about the enzyme responsible for conversion of
> N-acetyl to N-glycolylneuraminic acid? Has it been cloned, if so has anyone
> got the cDNA?
>> *********************************************************
>> Prof. Nigel Jenkins
>njenkins at dmu.ac.uk> School of Applied Sciences
> De Montfort University
> Leicester LE1 9BH, U.K.
> Tel:++116 257 7118
> Fax:++116 257 7287
>> ---------------------------------------------------------------
> Iain Wilson Institut fuer Chemie
> Tel: 43-1-47654-6065 Universitaet fuer Bodenkultur
> Fax: 43-1-310-5176 Gregor-Mendel-Strasse 33
> E-mail: wilson at edv1.boku.ac.at A-1180, WIEN, Austria
>>>To Prof. Jenkins and others who are interested:
I'm not really an expert in this particular area, but I am
familiar with one or two key papers, which should be quite informative.
The conversion of NeuAc to NeuGc actually occurs at the level of the
nucleotide sugar: CMP-NeuAc is converted to CMP-NeuGc.
The key work has been done by Akemi Suzuki and co-workers. They
published data (Y. Kozutsumi et al., J. Biochem 108, 704-6, 1990) supporting
the hypothesis that the conversion was done by a three enzyme complex,
cytochrome b5, NADH dependent cytochrome b5 reductase, and CMP-NeuAc
hydroxylase, of which the last seems to be the rate limiting step.
Last year the same group published the purification of the NeuAc
hydroxylase from mouse liver (T. Kawano et al., J. Biol. Chem. 269, 9024-9,
1994). The enzyme is a 64 kDa polypeptide. They state in this paper
(published in March '94) that cDNA cloning is in progress.
I hope this helps.
Jim Mahoney
Dept. of Pharmacology
Johns Hopkins School of Medicine
