Abstract:
The cyclic enediynes, a relatively new class of
antitumor antibiotics are strong DNA cleavage agents
and exhibit remarkable antitumor activities both in
vitro and in vivo. Naturally occurring enediyne
antitumor antibiotics are divided into two groups
according to the 9- or 10-membered ring core
structure. The first enediyne antibiotic,
neocarzinostatin (NCS) consisting of 1:1 mixture of an
apoprotein and a chromophoric molecule (shown inFigure 1.1), was isolated from Streptomyces
carzinostaticus in 1965. However, the structure of the
NCS chromophorewas determined twenty years later.
Following the disclosure of the unprecedented
molecular structure of neocarzinostatin, two families
of 10-membered ring enediynes were discovered in
1987, as represented by calicheamicin from
Micromonospora echinospora and esperamicin-A
1
from Actinomadura verrucospora.