{PDOC00001}
{PS00001; ASN_GLYCOSYLATION}
{BEGIN}
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* N-glycosylation site *
************************

It has been known for a long time [1] that potential N-glycosylation sites are
specific to the consensus sequence Asn-Xaa-Ser/Thr.  It must be noted that the
presence of the consensus  tripeptide  is  not sufficient  to conclude that an
asparagine residue is glycosylated, due to  the fact that the  folding of  the
protein plays an important  role in the  regulation of N-glycosylation [2]. It
has been shown [3] that  the  presence of proline between Asn and Ser/Thr will
inhibit N-glycosylation; this  has  been confirmed by a recent [4] statistical
analysis of glycosylation sites, which also  shows that about 50% of the sites
that have a proline C-terminal to Ser/Thr are not glycosylated.

It must also  be noted that there  are  a few  reported cases of glycosylation
sites with the pattern Asn-Xaa-Cys; an  experimentally demonstrated occurrence
of such a non-standard site is found in the plasma protein C [5].

-Consensus pattern: N-{P}-[ST]-{P}
                    [N is the glycosylation site]
-Last update: May 1991 / Text revised.

[ 1] Marshall R.D.
     Annu. Rev. Biochem. 41:673-702(1972).
[ 2] Pless D.D., Lennarz W.J.
     Proc. Natl. Acad. Sci. U.S.A. 74:134-138(1977).
[ 3] Bause E.
     Biochem. J. 209:331-336(1983).
[ 4] Gavel Y., von Heijne G.
     Protein Eng. 3:433-442(1990).
[ 5] Miletich J.P., Broze G.J. Jr.
     J. Biol. Chem. 265:11397-11404(1990).
{END}