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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New";color:blue'>Regarding my email below, I’d just like to thank all for taking the time to provide their any comments and insights in response to my question.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New";color:blue'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New";color:blue'>Best regards<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New";color:blue'>John Sumida<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New";color:blue'>University of Washington<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New";color:blue'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> John Sumida [mailto:jpsumida@u.washington.edu] <br><b>Sent:</b> Tuesday, January 20, 2015 6:01 PM<br><b>To:</b> rasmb@rasmb.org<br><b>Subject:</b> concentration range for non-ideal behavior<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>Dear RASMB,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>My recollection is that concentrations in excess of 1.0 mg/ml should be avoided due to the possibility of non-ideal interactions that would complicate the analysis of SV and SE measurements. However in two recent cases (in one case a mAb was being studied, and in another a globular viral capsid protein), we exceeded this value by a factor of five and failed to observe any evidence of non-ideal behavior. In both cases, it was possible to fit both SV and SE data without assuming any non-ideal interactions when the experiment was performed in PBS or HEPES.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>I would be curious to hear if it is the experience of the community that non-ideality is commonly to be expected at concentrations >1.0mg/ml or whether the concentration cutoff for non-ideality is less of an actual cutoff being more a function of the particular properties of the molecule being studied.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>Best regards<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>John Sumida<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>University of Washington<o:p></o:p></span></p></div></body></html>