Details

Autor(en) / Beteiligte

• Rae, Tracey Douglas
• Rupprecht, Kevin
• Bonn, Ryan
• Stamenova, Svetoslava
• Zhao, Cheng
• Ramsay, Carol
• Fishpaugh, Jeffrey

Titel

A comparative analysis of native neutrophil gelatinase‐associated lipocalin (NGAL) protein isolated from various human source matrices

Ist Teil von

• The FASEB journal, 2011-04, Vol.25 (S1), p.923.3-923.3

Ort / Verlag

Federation of American Societies for Experimental Biology

Erscheinungsjahr

2011

Quelle

Wiley Online Library Journals Frontfile Complete

Beschreibungen/Notizen

• Elevated levels of Neutrophil Gelatinase Associated Lipocalin (NGAL) in the urine have been established as a promising diagnostic indicator for acute kidney injury (AKI). Although significant structural information on the human NGAL protein has been revealed from work with various recombinant expression systems, less has been revealed from native NGAL protein species produced in human leukocytes and secreted in the urine. Development of a quantitative diagnostic immunoassay for NGAL in urine prompts an understanding of the native protein analyte and its structural similarity to a biosynthetic recombinant protein used to calibrate the assay. Here we present a comparative analysis of human NGAL protein isolated from both leukocytes and urine sources. Multiple analytical techniques were applied to assess differences in protein charge, oligomeric state, molecular mass and post‐translational modifications. Affinity‐purified NGAL protein from both human leukocytes and a human urine specimen pool was also found to display significant visible spectrum absorbance indicative of an iron siderophore‐like substrate as speculated by previous work. This apparent substrate is shown to be tightly bound to the protein, as the protein retains the visible spectrum absorptivity through HPLC chromatographic separation. The purified protein also was found to contain a significant amount of iron by ICP‐MS. Implications from the observed structural differences and substrate characteristics on the protein function and behavior in clinical immunoassays are discussed.