Patent ID: 8481254

Claim:
A substrate probe for use in measuring enzyme activity by using a three-dimensional nuclear magnetic resonance method, wherein the probe has an enzyme recognition site, which is selectively recognized by an active-state enzyme, and wherein a first nuclear magnetic resonance active nuclei having a nuclear spin, a second nuclear magnetic resonance active nuclei having a nuclear spin, and a third nuclear magnetic resonance active nuclei having a nuclear spin are present in the enzyme recognition site, wherein the second nuclear magnetic resonance active nuclei is connected to the first nuclear magnetic resonance active nuclei and the third nuclear magnetic resonance active nuclei is connected to the second nuclear magnetic resonance active nuclei, wherein each of the first, second, and third nuclear magnetic resonance active nuclei has a different resonance frequency, wherein the probe is pyruvic acid or a salt thereof, and wherein a carbon at a 2-position and a carbon at a 3 position of the pyruvic acid or the salt thereof are labeled with 13 C and a hydrogen atom bound with the carbon of the 3-position of the pyruvic acid or the salt thereof is deuterated.