sometime it does happen becoz of protein aggregation, or reducing environment. but it may be your protein color as well that visible during concentration Vikrant
________________________________ From: sandeep <toskgu...@rediffmail.com> To: CCP4BB@JISCMAIL.AC.UK Sent: Fri, 24 September, 2010 2:04:54 PM Subject: [ccp4bb] protein turns brown Dear all, I have purified protein from E.coli. expression system. the protein has been purified with three independant columns. Now during concentration step using amicon, the protein shows brown colour. what could be the reason. best regards and Thanks, sandy
