Measuring method and composition using kinase

A measuring method for at least one of creatine, creatine phosphate, and creatinine, comprising:

• (1) conducting a cycling reaction according to the following Formula (1):
• by bringing:
• i) a creatine kinase capable of catalyzing a forward reaction for producing the creatine phosphate from the creatine and a reverse reaction thereof in the presence of nucleotide coenzymes, the kinase being capable of utilizing nucleotide coenzymes at least having different nucleoside moieties in the forward reaction and the reverse reaction, respectively,
• ii) a first nucleotide coenzyme, and
• iii) a second nucleotide coenzyme having a different nucleoside moiety from the first nucleotide coenzyme
• into contact with a sample or a sample having been subjected to a quantitative derivation treatment from the creatinine to the creatine and/or the creatine phosphate in a case where a measurement target is at least the creatinine;
• (2) detecting an amount of change of a signal corresponding to a change of at least any one of the first nucleotide coenzyme, a conversion product of the first nucleotide coenzyme, the second nucleotide coenzyme, and a conversion product of the second nucleotide coenzyme;
• and
• (3) calculating, on the basis of the detected change of the signal, an amount of at least one of the creatine, the creatine phosphate, and the creatinine.