The p300/CBP Colorimetric Cell-Based ELISA Kit is a convenient, lysate-free, high throughput and sensitive assay kit that can detect p300/CBP protein expression profile in cells. The kit can be used for measuring the relative amounts of p300/CBP in cultured cells as well as screening for the effects that variuos treatments, inhibitors (ie siRNA or chemicals), or activators have on p300/CBP.