Ap. Guzikowski et al., Synthesis of a macrocyclic rhodamine 110 enzyme substrate as an intracellular probe for caspase 3 activity, TETRAHEDR L, 41(24), 2000, pp. 4733-4735
The synthesis of the macrocyclic rhodamine 110 caspase 3 substrate 8 is des
cribed. The key step is a high dilution intramolecular cyclization reaction
of an in situ generated primary amine with a 4-nitrophenyl ester. Substrat
e 8 reacts with recombinant caspase 3 to yield a fluorescent signal but vir
tually no signal is detected in the absence of caspase 3 or in the presence
of the caspase 3 inhibitor Ac-DEVD-CHO. Notably, 8 selectively stains live
cells that have been induced to undergo apoptosis with etoposide. (C) 2000
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