Table 1.
Comparison of the five human tear proteome studies concerning healthy subjects published since 2005
| Study | Sample (n) | Collection method | Amount used | Fractioning | No. of fractions | Enzymatic digestion | Online LC column | Gradient length, flow | Spectrometer | MS mode | Data analysis software | No. of protein IDs |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Li et al. (2005) | One individual, single take | Open‐eye MCT | 1 µl SDS‐PAGE | SDS‐PAGE | 10 | Trypsin | None | None | Reflex III MALDI‐TOF (Bruker) | Full scan | Mascot | 17 |
| 5 µl in solution | None | 0 | Trypsin | 150 µm × 150 mm, ND particle size, ND Å | 120–200 min, 1 µl/min | LCQ Deca (Thermo); QSTAR Pulsar QqTOF (ABSciex) | DDA | Mascot | 52 | |||
| de Souza et al. (2006) | One individual, different takes | Closed‐eye MCT | 4 µl SDS‐PAGE | SDS‐PAGE | 13 | Trypsin | ND | ND | LTQ‐FT (Thermo) | DDA | Mascot and MSQuant | 320 |
| 1 or 4 µl in solution | None | 0 | 1. Lys‐C | ND | ND | LTQ‐FT, LTQ‐Orbitrap (Thermo) | DDA | Mascot and MSQuant | 63 | |||
| 2. Trypsin | ||||||||||||
| Zhou et al. (2012) | Pool (4 individuals) | STS | ~400 µg TP | Off‐line SCX | 6 | Trypsin | 75 µm × 500 mm, 2 µm particle size, 100 Å | 60 min, 300 nl/min | Triple TOF 5600 (ABsciex) | DIA | ProteinPilot | 1543 |
| Aass et al. (2015) | Pool (3 individuals) | STS | ND | Off‐line SCX | 16 | 1. Lys‐C | 1.0 × 250 mm, 5 µm particle size, 100 Å | 180 min, 40 µl/min | LTQ Orbitrap XL (Thermo) | DDA | Proteome Discoverer | 1526 |
| 2. Trypsin | ||||||||||||
| Dor et al. (2019) | Pool (2 or 3 individuals) | STS | 60 µg TP | Off‐gel electrophoresis | 12 | Trypsin | 75 µm × 150 mm, 5 µm particle size, 100 Å | 85 min, 220 nl/min | LTQ Orbitrap Velos Pro (Thermo) | DDA | Proteome Discoverer | 1351 |
Abbreviations: DDA, data‐dependent acquisition; DIA, data‐independent acquisition; FT, Fourier transform; LC, liquid chromatography; LTQ, linear trap quadrupole; MALDI, matrix‐assisted laser desorption ionization; MS, mass spectrum; MCT, microcapillary tube; ND, not defined; SCX, strong cation exchange chromatography; SDS‐PAGE, sodium dodecyl sulfate–polyacrylamide gel electrophoresis; STS, Schirmer's test strip; TOF, time‐of‐flight; TP, total proteins.