The Cytochrome P450 4B1 Colorimetric Cell-Based ELISA is a convenient, lysate-free, high throughput and sensitive assay kit that can detect CytochromeP4504B1 protein expression profile in cells. The kit can be used for measuring the relative amounts of CytochromeP4504B1 in cultured cells as well as screening for the effects that variuos treatments, inhibitors (ie siRNA or chemicals), or activators have on CytochromeP4504B1.