%0 Journal Article %A Aslanzadeh, Jaber %A Brown, Eric J. %A Quillin, Shawn P. %A Ritchey, Julie K. %A Ratliff, Timothy L. %T Characterization of Soluble Fibronectin Binding to Bacille Calmette-Guérin %D 1989 %J Microbiology, %V 135 %N 10 %P 2735-2741 %@ 1465-2080 %R https://doi.org/10.1099/00221287-135-10-2735 %I Microbiology Society, %X Froromectin (FN), a 420 kDa glycoprotein, consists of two similar subunits linked by a disulpthide bond near the C-terminal end. FN is present in soluble and matrix forms in various body fluids and tissues and has been shown to bind to a variety of organisms. We characterized the conditions required for 125I-FN binding to Bacille Calmette-Guérin (BCG). The binding was dose-dependent, reached saturation within 3 min, and was essentially irreversible for at least 24 h under optimal binding conditions at pH 6·0. In contrast, the binding was reversible (> 90% in 24 h) when the pH was increased to 10·0. Scatchard analysis of the dose-response expreiments produced a straight line, suggesting the presence of a single class of FN receptor on BCG. 125I-FN binding was trypsin-sensitive, suggesting that the BCG-binding molecule is a protein. The number of FN receptors was determined to be 8000–15000 per bacterium. 125I-FN binding was pH dependent, with maximal binding at acidic pH. 125I-FN binding was sensitive to the presence of NaCl, with 0·08 m-NaCl inhibiting binding by 85%. These data demonstrate that soluble FN binds to a trypsin-sensitive cell-surface component of BCG in an essentially irreversible manner. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-135-10-2735