Hi Yue Li, are you sure that it's the sulfate that competes with the inhibitor binding, say, from enzymatic test? It could be, but it is known that sulfates and phosphates usually prefer different binding sites ...
Best regards, Dirk. Yue Li wrote: > Hi all, > > I have crystals of the apo enzyme growing from 1.7M ammonium sulfate > condition. After soaking with 10mM ligand (substrate analog) which has a > phosphate group, the ligand did not enter the active site of the enzyme > because of the competition of sulfate ion and phosphate group. So I am > wondering if anyone knows how to get rid of ammonium sulfate from > crystal before soaking it with the ligand solution? Thanks a lot. > > Simon -- **************************************** Dirk Kostrewa Paul Scherrer Institut Biomolecular Research, OFLC/110 CH-5232 Villigen PSI, Switzerland Phone: +41-56-310-4722 Fax: +41-56-310-5288 E-mail: [EMAIL PROTECTED] http://sb.web.psi.ch ****************************************
