Enzyme plays an extremely important role in maintaining homeostasis and the normal life activities in biological systems.The abnormality of some particular enzymes activity is closely relevant to the occurrence and development of related diseases.Therefore

it is of great significance to detect and visualize specific enzyme in vivo with an in-situ and real-time method.The chemical fluorescent probes are endowed with the obvious advantages such as good selectivity

high sensitivity

high imaging resolution and so forth.In recent years

researchers have designed and synthesized a series of fluorescent probes for enzyme detection and visualized imaging in living systems.Based on the trigger mode of fluorescence response

the enzymatic fluorescent probes can be generally divided into two categories:(1) probes based on the recognition between enzyme and specific groups of its inhibitor existing in the probes

called inhibitor-based enzymatic fluorescent probes and(2) probes based on the effective catalytic ability of specific enzyme

also known as the reaction-activated enzymatic fluorescent probes.Herein

in this review

the design strategies of reaction-activated fluorescent probe for enzymes and the research progress of reaction-activated fluorescent probes for four important disease-related enzymes(monoamine oxidase

β-galactosidase

nitroreductase

γ-gumatyl transpeptidase) were mainly reviewed

and the future research of fluorescent probes for enzymes was prospected.