This invention characterizes the specific peptide fragment derived from
specially prepared zinc charged fetuin and a method of preparation
thereof, wherein the fragment was found to contain an apoptosis-inducing
activity. Specifically, the amino acid sequence of this peptide is
His-Thr-Phe-Met-Gy-Val-Val-Ser-Leu-Gly (SEQ ID NO: 3) and correlates to
amino acid no. 300-309 of bovine fetuin, referred to herein as Fetuin
Peptide Fragment (FPF 300-09). FPF 300-09 strongly induced apoptosis in
LNCaP (prostate cancer) and HT-29 (colon cancer) cells without affecting
CCD 18 Co (normal colon) cells. The in vitro tissue culture study
demonstrated that the FPF 300-09 is more potent than the parent molecule
(full-length zinc charged fetuin) in inducing apoptosis. FPF 300-09 has a
LD.sub.50 of 0.3-0.4 .mu.M, while the LD.sub.50 for zinc-charged fetuin
is 3-10 .mu.M.