To develop a new molecular sensor using an RNA-peptide conjugate, and to provide a detective method and a system therefor for various molecules through utilizing the sensor.

This new molecular sensor, i.e. a ribonucleopeptide fluorescence sensor, is produced by producing an RNA-peptide conjugate( ribonucleopeptide ) highly selectively bindable to adenosine triphosphate(ATP) by using an in vitro selection technique and then modifying the N-terminal group of the peptide subunit of the conjugate with a fluorescent molecule. The fluorescence sensor thus obtained can detect the substrate ATP in a real-time manner and quantify it because of having the property of significantly increasing its fluorescence intensity when the substrate ATP is bound to the sensor.