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JP-2026075341-A - Method, labeled tyrosine molecule, and diagnostic agent

JP2026075341AJP 2026075341 AJP2026075341 AJP 2026075341AJP-2026075341-A

Abstract

[Challenge] One of the challenges is to provide a labeled tyrosine molecule that can be excited to a hyperpolarized state, and a method that utilizes this molecule. [Solution] A method comprising: a first step of exciting a labeled tyrosine molecule represented by formula (1) in a basic solution by dynamic nuclear polarization to obtain hyperpolarized labeled tyrosine; and a second step of performing NMR observation on a sample containing the hyperpolarized labeled tyrosine. In formula (1), R1 is independently a hydrogen atom or a deuterium atom, R2 is independently a hydrogen atom or a deuterium atom, and R3 is independently a hydrogen atom or a deuterium atom. [Chemical formula 1] [Selection Diagram] None

Inventors

  • 金子 大智
  • 横山 順
  • 高草木 洋一
  • 齋藤 圭太

Assignees

  • 日本酸素株式会社
  • 国立研究開発法人量子科学技術研究開発機構

Dates

Publication Date
20260508
Application Date
20241022

Claims (12)

  1. The first step involves exciting a labeled tyrosine molecule represented by formula (1) in a basic solution using dynamic nuclear polarization to obtain hyperpolarized labeled tyrosine, and A method comprising: a second step of performing NMR observation on a sample containing the hyperpolarized labeled tyrosine. [In formula (1), R1 is independently a hydrogen atom or a deuterium atom, R2 is independently a hydrogen atom or a deuterium atom, and R3 is independently a hydrogen atom or a deuterium atom.]
  2. The method according to claim 1, wherein the basic solution contains hydroxide ions, and the concentration of the hydroxide contained in the basic solution is greater than 1 M.
  3. The method according to claim 1, wherein the sample is a sample solution containing water, its pH is adjusted to 5.0 to 8.0, tyrosinase is added to the sample, and the metabolites of the hyperpolarized labeled tyrosine are generated in the sample by the enzymatic reaction.
  4. The method according to claim 3, wherein at least one of the signals S1 attributed to the molecular structure of the hyperpolarized labeled tyrosine and the signal S2 attributed to the molecular structure of the metabolite is observed by NMR observation.
  5. The method according to claim 4, comprising performing multiple NMR observations and observing at least one of the change in signal S1 and the change in signal S2.
  6. The method according to claim 3, wherein the tyrosinase incorporated into the sample is an oxy-type tyrosinase that has obtained monophenolase activity by reacting with catechols or 3-hydroxykynurenine beforehand.
  7. The method according to claim 1, wherein the sample contains cells, and at least one of the following signals is observed: signal S1, which is attributed to the molecular structure of the hyperpolarized labeled tyrosine taken up into the cells, and signal S2, which is attributed to the molecular structure of a metabolite metabolized by an enzyme reaction present in the cells.
  8. The method according to claim 7, wherein the sample is a biological organism having the cells.
  9. The method according to claim 7 or 8, comprising performing multiple NMR observations, observing at least one of the changes in signal S1 and signal S2, and determining that the cells have the potential to form melanoma or melasma if the change is greater than or less than a predetermined criterion.
  10. A labeled tyrosine molecule represented by formula (1). [In formula (1), R1 is independently a hydrogen atom or a deuterium atom, R2 is independently a hydrogen atom or a deuterium atom, and R3 is independently a hydrogen atom or a deuterium atom.]
  11. A diagnostic agent comprising the labeled tyrosine molecule described in claim 10.
  12. A method comprising the step of exciting a water-insoluble organic compound having one or more 13C atoms in its molecule by dynamic nuclear polarization in a basic solution to obtain a hyperpolarized water-insoluble organic compound.

Description

This invention relates to an NMR observation method using dynamic nuclear polarization. NMR (magnetic resonance spectroscopy) and MRI (magnetic resonance imaging) methods precisely observe the nuclear spins of atoms in a material under a strong static magnetic field, and extract rich information about molecular structure from electromagnetic wave signals (NMR signals) modulated by interactions between nuclear spins. The sensitivity of the NMR signal is proportional to the polarization rate, and dynamic nuclear polarization (DNP) is used as a technique to dramatically improve measurement sensitivity by increasing the polarization rate by several orders of magnitude. The ¹³C nuclear spins hyperpolarized (highly polarized) by DNP decay in a few seconds to tens of seconds due to modulation of the magnetic field caused by molecular motion and interactions inside and outside the molecule. The time it takes for the polarization to decay to a predetermined percentage is generally expressed as the longitudinal relaxation time ( T1 relaxation time). If a hyperpolarized compound can function as an enzyme substrate and its longitudinal relaxation time is several tens of seconds, the metabolism of the substrate by the enzymatic reaction occurring within that time can be observed. For example, Non-Patent Literature 1 describes a method for observing in real time the process by which [ 1-13C ]-pyruvic acid is metabolized in cancer cells of various organs. To observe such metabolic processes, it is preferable to use a substrate with a long longitudinal relaxation time, which serves as an indicator of polarization lifetime, as a molecular probe. Patent Document 1 discloses aromatic compounds with longer longitudinal relaxation times than conventional compounds. According to Patent Document 1, it is reported that by utilizing the long-lived state of two 13C nuclear spin pairs at the ring-condensed carbon of the naphthoic acid skeleton, the longitudinal relaxation time can be extended by approximately five times. Peder E. Z. Larson et al., Current methods for hyperpolarized [1-13C]pyruvate MRI human studies. Reason. Med. 2024;91:2204-2228. International Publication No. 2024/014325 Figure 1 shows the results of a test in which an enzymatic reaction by tyrosinase using a labeled tyrosine molecule as a substrate was observed in real time using NMR.Figure 2 shows the results of a test in which an enzymatic reaction by tyrosinase using a labeled tyrosine molecule as a substrate was observed in real time using NMR.Figure 3 shows the integrated spectrum obtained by combining the spectra from scans 1 to 10 in Figure 1. The embodiments of the present invention will be described in detail below, but the present invention is not limited to the embodiments described later, and various modifications are possible as long as they do not depart from the spirit of the invention. The meanings and definitions of terms used in this specification are as follows: A numerical range represented by "~" means a range of numbers whose lower and upper limits are the numbers before and after "~". "Hyperpolarized compounds" can be rephrased as highly polarized compounds, and refer to compounds in which nuclear spin polarization has been increased by dynamic nuclear polarization. Unless otherwise specified, "hydrogen atom" refers to a light hydrogen atom. In chemical formulas, "D" represents a deuterium atom. Unless otherwise specified, "amino acids" can be either L-type or D-type, but the L-type, which is abundant in nature, is preferred. ≪Labeled Tyrosine Molecules≫ A first aspect of the present invention is a labeled tyrosine molecule represented by formula (1). In formula (1), each R1 is independently a hydrogen atom or a deuterium atom, each R2 is independently a hydrogen atom or a deuterium atom, and each R3 is independently a hydrogen atom or a deuterium atom. In this embodiment, it is preferable that at least one of the two R1 atoms bonded to the aromatic ring is a deuterium atom. By having at least one, preferably two, of the R1 atoms bonded to the aromatic ring be deuterium, the interaction with 13C is reduced compared to when R1 is a light hydrogen atom, and the longitudinal relaxation time of the hyperpolarized 13C nucleus can be lengthened. Labeled tyrosine molecules in which both R1 and R2 are light hydrogen atoms can be purchased commercially. One method for substituting these with deuterium atoms is to place the labeled tyrosine molecules in a solution of deuterated trifluoromethanesulfonic acid as a solvent and perform hydrogen-deuterium exchange. The labeled tyrosine molecule of this embodiment can be applied to the use of hyperpolarized molecular probes. For example, by administering a molecular probe hyperpolarized by the DNP method to an enzyme reaction solution, cells, or living organism, and then observing it using NMR or MRI, it is possible to observe in real time the metabolic process of the molecular probe due to the enzymatic rea