Fig. 2.

Synthesis and in vitro activity of mitoDPP-2. a Synthetic scheme for mitoDPP-2. b In vitro fluorescence assay of mitoDPP-2 (1 µM) in HEPES (20 mM, pH 7.4, 150 mM NaCl, 0.1% Triton X-100) with either 50 nM purified APT1 or APT2 (λ_ex 490/20 nm, λ_em 545/20 nm). Error bars are ± s.e.m. (n = 3). c Fluorescence emission spectra at 30 min from probes as treated in (b). d UV–vis spectra of 25 µM mitoDPP-2 (black; normalized at 275 nm) and deprotected fluorophore product (gray; normalized at 513 nm) in HEPES (20 mM, pH 7.4, 150 mM NaCl, 0.1% Triton X-100). MitoDPP-2 shows UV–vis absorbance at 300 nm with extinction coefficient 8.7 × 10³ M⁻¹ cm⁻¹. The deprotected fluorophore product shows a major UV-Vis absorbance peak at 513 nm with extinction coefficient 11.8 × 10³ M⁻¹ cm⁻¹