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- Escribano, Julio, et al.
(författare)
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Identification of retinol as one of the protein HC chromophores
- 1988
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 0006-291X. ; 155:3, s. 1424-1429
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Tidskriftsartikel (refereegranskat)abstract
- Protein HC (alias alpha 1-microglobulin) contains so far unidentified yellow-brown fluorescent chromophores. Several preparations of human protein HC were extracted with hexane. Most of the extracts contained a substance which, upon reversed-phase HPLC, co-eluted with all-trans- retinol and had an absorption spectrum identical to that of retinol. The substance was also, like retinol, destroyed by exposure to ultraviolet light and acid pH. These observations strongly support the proposal that protein HC is a member of the newly defined lipocalin protein superfamily. The highest retinol-protein HC molar ratio of the investigated protein HC preparations was 1.6 x 10(-3) indicating that retinol is not the only ligand bound to protein HC. This was confirmed by comparing the absorption spectrum of protein HC before and after hexane extraction.
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| 2. |
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| 3. |
- Méndez, Enrique, et al.
(författare)
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Human protein HC and its IgA complex are inhibitors of neutrophil chemotaxis
- 1986
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 83:5, s. 1472-1475
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Tidskriftsartikel (refereegranskat)abstract
- Protein HC, a heterogeneously charged low molecular weight glycoprotein, and its IgA complex were isolated from human plasma and urine. Plasma from individuals with monoclonal IgA populations was used as starting material for the isolation of the protein HC-IgA complex to obtain homogeneous complex populations. Neither low molecular weight protein HC nor its IgA complex in the concentrations 30 and 600 mg/liter influenced the random migration of normal human neutrophils. The chemotactic response of neutrophils to endotoxin-activated serum was, however, attenuated in a dose-dependent way by both low molecular weight protein HC and protein HC-IgA complex. Concentrations of protein HC and its IgA complex producing significant inhibition of the chemotactic response were found to occur in plasma from healthy and diseased individuals as well as in synovial fluid from patients with rheumatoid arthritis. These results suggest that protein HC and its IgA complex play physiological roles in the regulation of the inflammatory response.
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