Hi Jenny,
Sometimes the buffer itself, not just the pH, can affect the behaviour of a protein. If in Tris or phosphate, try HEPES, for example. This can have in some cases a dramatic effect on protein solubility. Is the column clogging when you apply the sample (are you using DNase/RNase, centrifuging the sample sufficiently and/or filtering it), when you wash (avoid calcium with phosphate buffers), or when you elute (try changing the type of buffer you are using)?
James
-- Dr. James Irving
NH&MRC C.J. Martin Fellow
Division of Structural Biology
Wellcome Trust Centre for Human Genetics
Oxford University
Roosevelt Drive
Headington,
Oxford OX3 7BN
UK
email: [EMAIL PROTECTED]
phone: +44 1865 287 550 (temporary)
