Are you boiling your samples? Seems funny that under SDS PAGE there should be dimers, unless there is a disulfide link. If so, reducing agents (DTT, TCEP, BME) should take care of this.
JPK From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Smith Liu Sent: Tuesday, June 27, 2017 8:41 AM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] Separating Monomers and Dimers it was not stable for frozen storage. if necessary，using protein fresh without frozen 发自网易邮箱大师 在2017年06月27日 20:22，jai mohan<mailto:00000cab66323371-dmarc-requ...@jiscmail.ac.uk> 写道： Dear all, I am working on a Red Fluorescent Protein (His-Tag) molecular weight around 27kDa. After purification I ran a SDS page, the band at 27kDa confirms the monomer. The protein was stored at -20C, a week later again I ran a gel, this time I saw another new band between 50-60kDa, it confirms the protein solution contains both monomers and dimers. I would like to know, what is the best way to separate the monomers and dimers? One of my colleague advice me to go for sucrose gradient centrifugation and size exclusion chromatography. However, I seek all your valuable suggestions and advice. With best regards Dr. S.M.Jaimohan
