Reporter Enzyme-Nitrilo-triacetic Acid-Nickel Conjugates: Reagents for Detecting Histidine-Tagged Proteins

摘要

As an aid to protein purification, re-combinant proteins are often linked to affinity tags. For example, nickel affinity columns can be used to purify re-combinant proteins with a histidine affinity tag. Here we report on the conjugation of the nickel-binding qua-dridentate chelator, nitrilotriacetic acid (NTA; Reference 4), to alkaline phos-phatase (AP), an enzyme commonly used in immunological assays. When charged with nickel ions, such conjugates can be used both to directly detect histidine-labeled recombinant proteins and, in immunological assays, to detect antibodies that have been labeled with a histidine tag.