What is the amount of antibody per ChIP to use?
It should be determined empirically for each target and antibody. For abundant proteins, like histones, use 1 to 2 µg of affinity purified or monoclonal antibody per IP. For other targets, use up to 10 µg per ChIP. To ensure efficient IP it is important to have an optimal ratio between the amount of chromatin and the amount of antibody. More antibody (or less chromatin) can be required in case of low affinity to antigen or high abundance of target protein (e.g. histones). Insufficient amount of antibody can result in low efficiency of ChIP whereas large excess of antibody might lead to lower specificity.
