diTyr-DTPA-Gd

diTyr-DTPA-Gd is a paramagnetic contrast agent designed for enzyme-mediated signal amplification (EMSA) in magnetic resonance imaging (MRI). It consists of a gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) core conjugated to two tyrosine residues. The molecule serves as a substrate for peroxidases, such as horseradish peroxidase (HRP). In the presence of peroxidase and hydrogen peroxide (often generated by glucose oxidase in a dual-enzyme system), diTyr-DTPA-Gd undergoes oxidative polymerization. These polymerized products exhibit higher relaxivity and are retained at the site of enzyme activity (e.g., a tumor targeted by an HRP-conjugated antibody), leading to localized and prolonged T1-weighted MR signal enhancement. It has been primarily investigated in preclinical research for the targeted imaging of EGFRvIII expression in glioblastoma multiforme models.

Other names

bis-tyramide-DTPA-Gdgadolinium diethylenetriaminepentaacetate-bis-tyramide