▎ 摘　　要

NOVELTY - Electrochemical sensor comprises a layer of adenine-labeled polypeptide-graphene composite modified on the surface of the glassy carbon electrode, the sequence characteristic of the polypeptide is, the polypeptide can be cut by corresponding protease, and the third amino acid of the cleavage site towards the carbon terminal is histidine, and the fourth amino acid is a side chain modified with lysine. USE - The electrochemical sensor is useful for detecting protease (claimed). ADVANTAGE - The electrochemical sensor has low background current and strong anti-interference ability. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing electrochemical sensor, comprising (i) mixing graphene nanoplatelets with solution of the adenine-labeled polypeptide ultrasonically for 30 minutes, discarding the remaining polypeptide at upper layer by centrifuging, centrifugal washing the obtained polypeptidegraphene composite for 3 times with a phosphate buffer solution and storing at 4 degrees C to obtain polypeptide-graphene complex, and (ii) shaking and dispersing step (i) prepared kaolin-labeled polypeptide-graphene complex with phosphate buffer solution, dropping 5 mu l mixed liquid on 3 mm diameter glassy carbon electrode surface, and air drying to obtain an electrochemical sensor.