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. Author manuscript; available in PMC: 2015 Aug 4.
Published in final edited form as: Chemistry. 2014 Jul 2;20(32):9840–9850. doi: 10.1002/chem.201402474

Figure 2.

Figure 2

Detecting enzyme activities through changes in T1 relaxation time caused by alterations in rotational tumbling times. Top Panel: The contrast agent, hydroxytyraminyl-glycylmethylDOTA [D-DOTA(Gd)]; Bottom Panel: Polymerization of the contrast agent by perixodiase slows the rotational tumbling time of the agent, which causes a decrease in the T1 relaxation time of the agent on a per-Gd basis. (C) MR images of the contrast agent at various gadolinium concentrations in the presence of peroxidase (+ Px) or in the absence of peroxidase (− Px) and hydrogen peroxide, demonstrating the detection of peroxidase enzyme activity. Reproduced with permission from (31a).