The Investigation Of The Isolation And Purification Of Marine Polypeptides From LD And Their Anti-tumor Activities

This paper presents the studies on the isolation, purification of polypeptides from marine-LD and their antitumor activities.The purified polypeptides LD 1 and LD 2 were obtained from LD by the combinations of technologies: homogenization, ammonia sulfate precipitation, ion exchange chromatography,Sephadex G-50 gel filtration chromatography,etc.As detected by RP-HPLC,the purity of the final products is over 98% which was further supported by Single band given in SDS PAGE and IEF. Their M.W measured by SDS-PAGE were 17100Da and 12900Da, isoeledric point were 5.1 and 5.5 respectively. The UV absorption spectrum and amino acid constituents of the purified products were also determined.Phenol- vitriol test revealed that saccharides exist in LD-1.The in vivo and in vitro pharmacological studies indicated that the total polypeptides from LD exhibited markedly antitumor activities in vivo and the tumor inhibitory rate on S180-bearing mice was 82.43%. The purified polypeptides LD-1 and LD 2 may both suppresed the growth of tumor cells G1o-82 in vitro, and the IC50 values were 19.95μg/ml and 12.43μg/ml respectively measured by MTT method.