Both the urinary
proteome and its glycoproteome can reflect human health status, and more directly, functions of kidney and urinary tracts. Because the high abundance
protein albumin is not N-glycosylated, the urine N-
glycoprotein enrichment procedure could deplete it, and urine
proteome could thus provide a more detailed
protein profile in addition to glycosylation information especially when
albuminuria occurs in some
kidney diseases. In terms of describing the details of urinary
proteins, the urine glycoproteome is even a better choice than the
proteome itself. Pooled urine samples from healthy volunteers were collected and
acetone-precipitated for
proteins. N-Linked
glycoproteins enriched with
concanavalin A affinity purification were separated and analyzed by SDS-PAGE-reverse phase LC/MS/MS or two-dimensional LC/MS/MS. A total of 225 urinary
proteins were identified based on two-hit criteria with reliability over 97% for each
peptide. Among these
proteins, 94 were identified in previous urine
proteome works, 150 were annotated as
glycoproteins in Swiss-Prot, and 43 were predicted as
glycoproteins by NetNGlyc 1.0. A number of known
biomarkers and disease-related
glycoproteins were identified. Because changes in
protein quantity or the glycosylation status can lead to changes in the
concanavalin A-captured
glycoprotein profile, specific urine glycoproteome patterns might be observed for specific pathological conditions as multiplex urinary
biomarkers. Knowledge of the urine glycoproteome is important in understanding kidney and body function.