小中大出现非特异性背景一般不是blocking的问题, 5%milk, 3%BSA室温一小时效果差不多.应该检测一抗二抗浓度是否过高,另外可增加洗涤次数,时间,TBS可加1%Tween20.
除非是磷酸化的抗体最好用BSA.
Block the membrane in 5% w/v BSA (fractionV) NOT MILK (milk contains casein which is a phosphoprotein; This is why it causes high background because the phospho-specific antibody detects the casein present in the milk).