α1-Microglobulin: a yellow-brown lipocalin

Åkerström, Bo; Lögdberg, Lennart; Berggård, Tord; Osmark, Peter; Lindqvist, Anna-Karin

doi:10.1016/s0167-4838(00)00157-6

Cited by 123 publications

(142 citation statements)

References 99 publications

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“…It is most abundant at interfaces between cells of the body and the environment, such as lungs, intestine, kidneys and placenta. a 1 -Microglobulin inhibits the immunological functions of white blood cells in vitro, and its distribution is consistent with an anti-inflammatory and protective role in vivo (20). Bikunin excretion increases in inflammatory conditions and is often considered to be a positive acute phase protein.…”

Section: Discussionmentioning

confidence: 96%

Proteomics of exhaled breath: methodological nuances and pitfalls

Kurova¹,

Анаев²,

Kononikhin³

et al. 2009

Clinical Chemistry and Laboratory Medicine

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Background: The analysis of exhaled breath condensate (EBC) can be an alternative to traditional endoscopic sampling of lower respiratory tract secretions. This is a simple non-invasive method of diagnosing respiratory diseases, in particular, respiratory inflammatory processes. Methods: Samples were collected with a special device-condenser (ECoScreen, VIASYS Healthcare, Germany), then treated with trypsin according to the proteomics protocol for standard protein mixtures and analyzed by nanoflow high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) with a 7-Tesla Finnigan LTQ-FT mass spectrometer (Thermo Electron, Germany). Mascot software (Matrixscience) was used for screening the database NCBInr for proteins corresponding to the peptide maps that were obtained. Results: EBCs from 17 young healthy non-smoking donors were collected. Different methods for concentrating protein were compared in order to optimize EBC preparations for proteomic analysis. The procedure that was chosen allowed identification of proteins exhaled by healthy people. The major proteins in the condensates were cytoskeletal keratins. Another 12 proteins were identified in EBC from healthy non-smokers. Some keratins were found in the ambient air and may be considered exogenous components of exhaled air. Conclusions: Knowledge of the normal proteome of exhaled breath allows one to look for biomarkers of different disease states in EBC. Proteins in ambient air can be identified in the respiratory tract and should be excluded from the analysis of the proteome of EBC. The results obtained allowed us to choose the most effective procedure of sample preparation when working with samples containing very low protein concentrations. Clin Chem Lab Med 2009;47:706-12.

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Section: Discussionmentioning

confidence: 96%

Proteomics of exhaled breath: methodological nuances and pitfalls

Kurova¹,

Анаев²,

Kononikhin³

et al. 2009

Clinical Chemistry and Laboratory Medicine

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“…The aggregate concentration in plasma of globulins with a molecular size similar to albumin, proteins such as transferrin, ␣ 1 -acid glycoprotein, ␣ 1 -proteinase inhibitor, ␣ 1 -antichymotrypsin, ␣ 2 -HS glycoprotein, hemopexin, Gc-globulin, and many others (31 ), in healthy individuals is ϳ25% that of albumin; this aggregate concentration is even higher during acutephase reactions (32 ). Because the passage of plasma proteins through the glomerular barrier into urine is primarily a size-dependent process with a size-exclusion limit approximately the size of albumin (33 ), it is not surprising that all of the albumin-sized plasma components are also found in urine (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(33)(34)(35)(36)(37)(38)(39). There is considerable variation in the reported proportions of individual globulins relative to albumin in urine (Table 3).…”

Section: Discussionmentioning

confidence: 99%

Coelution of Other Proteins with Albumin during Size-Exclusion HPLC: Implications for Analysis of Urinary Albumin

et al. 2006

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Background: Size-exclusion HPLC has been used as an alternative to immunoassays for quantifying urinary albumin (microalbumin). Systematically higher values for the HPLC method have been proposed to result from nonimmunoreactive albumin. Methods: We evaluated separation of purified proteins and urinary components by size-exclusion HPLC using a Zorbax Bio Series GF-250 column eluted with phosphate-buffered saline. Urinary components eluting in the "albumin" peak were analyzed by mass spectrometry and reversed-phase HPLC. Results: Several proteins, such as transferrin, ␣ 1 -proteinase inhibitor, ␣ 1 -acid glycoprotein, and ␣ 2 -HS glycoprotein, analyzed as purified components, were not resolved from albumin by size-exclusion HPLC. Peaks for other proteins, such as IgG and urinary components identified as dimers of ␣ 1 -microglobulin and immunoglobulin light chains, overlapped with the albumin peak. Profiles of urine specimens showed variable amounts of components overlapping with albumin. Furthermore, the albumin peak obtained by size-exclusion HPLC was found by mass spectrometry and reversedphase HPLC to contain multiple components in addition to albumin. Conclusions: Size-exclusion HPLC does not resolve albumin from several other proteins in urine. The albumin peak resolved by this technique, although predominantly composed of albumin, contains several coelut-

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“…It is an evolutionarily well-conserved plasma and tissue protein, which has been identified in mammals, birds, amphibians and fish [9,10]. α 1 m, also known as protein HC [11], is known to be mainly synthesised in the liver, although a minor expression of the protein has been seen in the pancreas and kidney [12,13].…”

Section: Introductionmentioning

confidence: 99%