摘要:
We designed and synthesized a new class of C-13-labeled NMR probe, C-13-IQ-Gd, to monitor one-electron reductions by cytochrome: P450 (CYP450) reductase under hypoxic conditions. C-13-IQ-Gd consisted of a Gd3+-diethylene triamine pentaacetic acid (DTPA) complex unit and an indolequinone (C-13-IQ) unit bearing a C-13-labeled methoxy group. The C-13 NMR signal of C-13-IQ-Gd was suppressed because of the intramolecular paramagnetic effect of Gd3+, whereas enzymatic reduction mediated by CYP450 reductase under hypoxic conditions yielded an intensed C-13 NMR signal due to enzymatic activation of the IQ unit followed by release of the DTPA-Gd unit from C-13-IQ-Gd. This C-13 NMR spectral change allowed the monitoring of CYP450 reducatase-mediated one-electron reduction. (C) 2010 Elsevier Ltd. All rights reserved.