Sirt1 molecular weight - (Jan/23/2015 )

Hi, I've a big question to solve my problem with Sirt1! The problem is this: when I use on mice muscle an anti-SIRT1 Abcam, I observe a band of 130 kDa after 2" of exposure, while I observe an additional band at 75 kDa after 2-3 minutes. I bought an antibody from Santa Cruz which work very well (and it recognize the C.terminus) only the band at 75 kDa after 3 minutes of exposure. Now! Which band should I consider?  The band at 130 kDa should be consider the real Sirt1 (as a lot of people do!) or it should be consider as a postr-translational form of Sirt1? Can anybody help me please????

Quick general answer without knowing specifics for this gene/protein:

1. Check all available published data on Sirt1 to learn more about isoforms and post-translationally (PT) modified forms.

2. Look up Sirt1 databases to see if any of these automated models talk about isoforms/PT forms. This link will help in searching many databases at one.

3. Specifically look up lit on mice muscle Sirt1 - it is possible that it may have a different spliced version/PT version of Sirt1.

4. Are other people using the same antibody? Here are most available Sirt1 antibodies.

3. Make sure you are denaturing the protein samples good. Sirt1 forms dimers (75+75=130 in gel!)

Hi CPRES,

thank a lot for your answer, it's very helpfull. Now I'll start to consider in particular point 2 and 3. I've already consider the other points. Thanks again