Mapping of peptides and protein fragments in human urine using liquid chromatography–mass spectrometry

Human Urinary Glycoproteomics; Attachment Site Specific Analysis of N- and O-Linked Glycosylations by CID and ECD

“…For healthy individuals, 30% of the urinary proteome has been estimated to originate from the plasma filtrate whereas the remaining 70% is believed to be derived from the kidneys and the urothelium (2). Until 2005, ϳ800 urinary proteins had been identified by various proteomic approaches (3)(4)(5)(6)(7). In 2006, a comprehensive proteomic study identified more than 1500 proteins from healthy human urine samples, simultaneously reflecting the complexity and the potential information concealed in the urinary proteome (8).…”

Analysis of the human urine endogenous peptides by nanoparticle extraction and mass spectrometry identification

“…Until recently, studies have shown that large quantities of peptides also appeared in urine [30,42]. However, the composition of the peptides in urine is not clearly understood.…”

“…On the other hand, some proteases in the urine still keep their activity at pH 2.7, thus still capable of degrading other proteins into fragments. It was reported that urine and other body fluid samples were acidified to pH 2.7 with hydrochloric acid immediately to prevent bacterial growth before analysis [6,30,46]. To check whether adjusting of the pH would affect the stability of the peptides in urine, the peptides in native state urine sample and acidified urine sample (pH 2.7) were extracted using the same procedure.…”

“…[27] used MALDI-TOF MSbased peptides profiling to successfully distinguish prostate, bladder, and breast cancer patients from healthy persons. However, there were only several reports on the study of peptidome in urine [28][29][30][31]. The large number of small peptides in urine provided the potential for disease diagnosis of the kidney function [32,33], while the peptidome of urine was not explored in-depth.…”

“…Solid phase extraction (SPE) is currently the most commonly used method to extract the peptides from urine [28][29][30][31], and is mainly based on their hydrophobicity but has no size selectivity. Nanoporous materials have shown great promise for sample pretreatment of body fluid in recent years [17,34,35].…”