 Other possibilities exist , as well . For example , immunohistochemistry usually utilizes an antibody to one or more proteins of interest that are conjugated to enzymes yielding either luminescent or chromogenic signals that can be compared between samples , allowing for localization information . Another applicable technique is cofractionation in sucrose ( or other material ) gradients using isopycnic centrifugation . While this technique does not prove colocalization of a compartment of known density and the protein of interest , it does increase the likelihood , and is more amenable to large @-@ scale studies . 
