[Determination of primary structure of a novel peptide from mistletoe and its antitumor activity].
OBJECTIVE
To study the antitumor peptide components in the stems and leaves of mistletoe (Viscum coloratum (Kom.) Nakai), the primary structure of the novel peptide was elucidated.


METHODS
Cation exchange, gel filtration and HPLC were employed for isolation and purification. Matrix Assisted Laser Desorption Ionization-Time of Flight-Mass Spectrometry was used to determine the mass. The complete amino acid sequence of the novel peptide was obtained by Edman degradation combined with enzyme digestion. The antitumor activity of the peptide in vitro was studied with MTT method.


RESULTS
The primary stucture of the peptide named as viscotoxin B2 is KSCCKNTTGRNIYNTCRFAGGSRERCAKLSGCKIISASTCPSDYPK. The IC50 value of viscotoxin B2 on the Rat Osteoblast-like Sarcoma 17/2.8 cells in vitro is 1.6 mg x L(-1).


CONCLUSIONS
Viscotoxin B2 in V. coloratum, which has high similarity with viscotoxins from V. album, showed antitumor activity.
Kong
Jing-lin
JL
Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China. jlkong@sina.com
Du
Xiu-bao
XB
Fan
Chong-xu
CX
Xu
Jian-fu
JF
Zheng
Xiao-jun
XJ
D000595:Amino Acid Sequence; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001859:Bone Neoplasms / Q000473:pathology; D020128:Inhibitory Concentration 50; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012516:Osteosarcoma / Q000473:pathology; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D018547:Plant Stems / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D051381:Rats; D014407:Tumor Cells, Cultured / Q000187:drug effects; D028181:Viscum / Q000737:chemistry*
D000972:Antineoplastic Agents, Phytogenic; D010455:Peptides; D010940:Plant Proteins