i am trying to express plant virus protease in bacterial expression system (prset a b c, invitrogen).
up to cloning it is ok but when i proceed for purification using 8m urea in all buffers (as per Genetix Ni NTA system) under denaturing conditions i didnt get band on sds page.
i didnt quantified it.
i used to boil the purified protein sample by adding loading dye but i cant see band on sds page.
what care should i taken during sample preparation for sds page?