2B-(A)

SI-2 is an inhibitor (SMI) of steroid receptor coactivator-3 (SRC-3 or AIB1). SI-2 can selectively reduce the transcriptional activities and the protein concentrations of SRC-3 in cells, and selectively induce breast cancer cell death with IC50 values in the low nanomolar range (3-20 nM), but not affect normal cell viability.

Levitide 是一种神经激素样肽，可从南非爪蟾 (Xenopus laevis) 的皮肤分泌物中分离出来。Levitide 来自前体 preprolevitide，它长 88 个残基，N 端是它的信号序列，C 端是 Levitide 肽 (Glu-Gly-Met-Ile-Gly-Thr-Leu-Thr-Ser-Lys-Arg-Ile-Lys-Gln-NH2)。