EFFECTS OF A SYNTHETIC POLYPEPTIDE ENCODED BY THE p14-6,A cDNA CLONE WITH ANTIONCOGENE ACTIVITY, ON MALIGNANT TRANSFORMED DT CELLS

A synthetic polypeptide, pt27, which is encoded by a cDNA clone with antloncogene activity, p14-6, is found to be able to reduce remarkably the soft agar colony formation ability of part of DT cells and to raise their resistance to the ouabaln toxtcity. This shows that the pt27 peptide can affect the DT cells In a manner similar to the p14- 6 done and provides evidence that the reverting action of the p14-6 to DT cells may be exerted by the expression of its cDNA.

Studies on the relationship between cyanide-resistant respiration and expression of alternative oxidase in mung bean using antibodies prepared by synthetic polypeptide

Twelve peptides, including eight conservative amino acid residues in the amino acid sequence of hydrophilic S helix of the alternative oxidase (AOX), were synthesized by solid-phase method. The polypeptide was coupled with α-chymotrypsinogen, and the antibodies were obtained through immunizing domestic rabbit by injecting this complex. By using these antibodies, which were raised to immunoreact with total proteins of purified mitochondria from different organs of mung bean seedlings, we find that there are two hybridizable AOX bands in mitochondria. Their molecular weights are about 35 and 38 ku, respectively. Moreover, the respiratory parameters of hypocotyl, true leaf and cotyledon of mung bean seedlings show that true leaf has the highest total respiration (Vt), alternative pathway (AP) capacity (Valt) and the activity of AP (ρValt) among the three organs. Vt and ρValt of cotyledon ranked the second. Hypocotyl has the lowest V, and ρValt, but its Valt is higher than that of cotyledon. These results are consistent with the analysis of Western blotting of expression of AOX. The highest Vt and ρValt in true leaf are accompanied two hybridizable polypeptides of AOX protein, 35 ku and 38 ku respectively. The next is cotyledon Vt and ρValt with only one 38 ku hybridizable polypeptide of AOX protein. Hypocotyl Vt and ρValt is the lowest and its immunoblotting band is similar to that of cotyledon, but the expressive amount of 38 ku protein is less than that of cotyledon. The results suggest that the 35 ku AOX may contribute mainly to true leaf ρValt.

Comparison of Structure and Biological Activity of Natural Polypeptide from Velvet Antlers of Cervus elaphus with Those of Synthesized Polypeptide

Biochemical techniques including ion-exchange chromatography, gel filtration chromatography and re- versed-phase high-performance liquid chromatography（RP-HPLC） were used to isolate and purify the natural poly- peptide from velvet antler（nVAP） of Cervus elaphus（C, elaphus）, which has a molecular weight of 3215.8 and the primary structure of VLSAADKSNVKAAWGKVGGNAPAFGAEALLRM. The homology of the protein sequence in nVAP with known protein sequence is less than 50%, suggesting that nVAP appears to be a new bioactive substance. At a level of 0.4--50 gg/mL, nVAP promotes mitosis in epidermal ceils, chondrocytes and NIH3T3 fibroblasts pri- marily cultured in a significant way. Given that a yield of high-purity nVAP isolated from C. elaphus is 0.001%, nVAP is artificially synthesized to prepare synthetic velvet antler polypeptide（sVAP） according to its primary struc- ture. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis（SDS-PAGE） of sVAP shows a single band, and its HPLC spectrum displays a single peak. The matrix-assisted laser desorption ionization time-of-flight mass spectro- metry（MALDI-TOF-MS） was used to identify sVAP to be of a molecular weight of 3200 and the consistency between primary structures of sVAP and nVAE Bioactivity test shows that at a dose of 5--40 μg/mL, sVAP promotes the pro- liferation of primarily cultured epidermal cells and NIH3T3 cell line. From the traditional Chinese medicine theory, velvet antler from Cervus nippon（C, nippon） and velvet antler from C. elaphus are considered as the same medicine, but differences between biochemical base and pharmacological effect of these two velvet antlers have been observed. We compared the total polypeptide mapping of the two velvet antlers, discovering that nVAP is active polypeptide and only exists in the velvet antler of C. elaphus, sVAP is similar to nVAP in physicochemical property and biological activity. These studies extend the possible utility of sVAP to be the promising compound to prepare velvet antler polypeptide of C. elaphus.