Significance of Urinary Proteome Pattern in Renal Allograft Recipients

Table 3

Salient features of techniques for urinary proteome analysis.

	Basic types	Specific techniques	Proteome types identified	Specific proteome identification probe/methods	Advantages	Disadvantages
1	Gel-based: electrophoresis on paper strip.	(a) Isoelectric focusing,; (b) SDS-PAGE,; (c) 2D-DIGE,	Proteins of 10 kDa and above	Western blotting and immune-blotting with specific antibodies against specific proteins.	Qualitative separation of proteins into low, middle, and high molecular weight protein (10 kDa and above)	Not often reproducible, quantitative assessment is difficult.
2	Gel-free: liquid chromatography, column/capillary electrophoresis with protein chips.	(a) MALDI-MS-TOF,; (b) SALDI-MS-TOF,; (c) iTRAQ	Peptides and small protein chains (less than 20 kDa)	MS with identification of 𝑚/𝑧 pattern.	High throughput. Multiple peptides can be assessed according to 𝑚/𝑧 chart with possible identification with known molecular weight.	Precise qualitative and quantitative isolation of individual peptide are not possible.

SDS-PAGE: sodium dodecyl sulfate polyacrylamide gel electrophoresis, 2D-DIGE: two-dimensional difference gel electrophoresis, MALDI: matrix assisted laser desorption-ionization, SELDI: surface enhanced laser desorption-ionization, MS: mass spectrometry, TOF: time-of-flight, iTRAQ: isobaric tags for relative and absolute quantification, kDa: kilo Dalton, and 𝑚/𝑧: molecular size and charge characteristics.