Genetic defects of the N-glycosylation pathway, named Congenital Disorders of Glycosylation (CDGs), result in abnormalities of N-glycome with aberrant glycan structures and changes in the relative levels of normal glycan moiety. Understanding N-glycan profile may be useful for characterization of known CDG types and to identify glycosylation processing defects in unsolved patients. CDG are heterogeneous disorders with variable clinical findings and multisystem involvement. As glycosylation defects are usually associated with abnormal glycoprotein folding and activity, it is plausible that the variety of clinical signs in CDG underlies abnormalities in a plethora of glycosylated molecules. Serum Transferrin was widely used so far to characterize N-glycan profile in patients with CDG; an alternative approach was based on the analysis of N-linked glycan released from total plasma. Our present work on N-glycome analyses in patients with CDG and related disorders is based on the systematic characterization, in addition to Transferrin, of multiple abundant serum glycoproteins, including acute-phase proteins. On this regard, we are working for creation of N-glycan profiling panel of each patient by the following steps: 1) purification of target glycoproteins by using sequentially, selective immunoaffinity columns on a few amount of unique serum sample. 2) characterization of the intact glycoprotein by MALDI mass spectrometry: this fundamental step allows us to analyze the rate and extent of deglycosylation (N-glycosylation site underoccupancy). 3) MALDI analyses of N-glycan structures. The observed occurrence of underglycosylation and abnormal glycan structure of AAT in CDG-Ia may link to possible unbalance of protease/antiprotease system in these patients.
Advances in Purification Methods of Serum Glycoproteins for MALDI-MS Analysis of N- Glycome in Patients with Glycosylation Disorders
Sturiale L;Barone R;Garozzo D
2006
Abstract
Genetic defects of the N-glycosylation pathway, named Congenital Disorders of Glycosylation (CDGs), result in abnormalities of N-glycome with aberrant glycan structures and changes in the relative levels of normal glycan moiety. Understanding N-glycan profile may be useful for characterization of known CDG types and to identify glycosylation processing defects in unsolved patients. CDG are heterogeneous disorders with variable clinical findings and multisystem involvement. As glycosylation defects are usually associated with abnormal glycoprotein folding and activity, it is plausible that the variety of clinical signs in CDG underlies abnormalities in a plethora of glycosylated molecules. Serum Transferrin was widely used so far to characterize N-glycan profile in patients with CDG; an alternative approach was based on the analysis of N-linked glycan released from total plasma. Our present work on N-glycome analyses in patients with CDG and related disorders is based on the systematic characterization, in addition to Transferrin, of multiple abundant serum glycoproteins, including acute-phase proteins. On this regard, we are working for creation of N-glycan profiling panel of each patient by the following steps: 1) purification of target glycoproteins by using sequentially, selective immunoaffinity columns on a few amount of unique serum sample. 2) characterization of the intact glycoprotein by MALDI mass spectrometry: this fundamental step allows us to analyze the rate and extent of deglycosylation (N-glycosylation site underoccupancy). 3) MALDI analyses of N-glycan structures. The observed occurrence of underglycosylation and abnormal glycan structure of AAT in CDG-Ia may link to possible unbalance of protease/antiprotease system in these patients.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
