O-linked sugars

I would like to check for the presence of Ser/Thr-O-GlcNAc on a protein.
Looking through the appropiate catalogues, I cannot find a lectin that
specifically labels this sugar group. I would be grateful if somebody could
give me details of how I may assay for this particular sugar linkage.

Thanks,

Kieran Breen, Dept. of Pharmacology,                  
University of Dundee,                   
Ninewells Hospital & Medical School,    
Dundee DD1 9SY,Scotland, U.K.                                              
               
k.c.breen at dundee.ac.uk