Ming Zhao

Synthesis and antithrombotic activity of carbolinecarboxyl RGD sequence

3S-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid, RGDS, RGDV, RGDF and their linkers were synthesized. The anti-aggregation and adhesion of platelet indicated that the in vitro activities of the linkers remained at the same level as RGDS, RGDV, and RGDF (p>0.05). The antithrombotic activities in vivo suggested, however, that the potencies of RGDS, RGDV and RGDF were enhanced by the introduction of 3S-1,2,3,4-tetrahydro-beta-carboline-3-carboxyl group into their alpha amino group (p<0.05, 0.01 or 0.001).

Synthesis and analgesic effects of kyotorphin-steroid linkers.

Kyotorphin (KTP, H-Tyr-Arg-OH) was covalently bonded with hydrocortisone or estrone to form the corresponding hydrocortisone-21-O-yl-succinyl-Tyr-ArgOH or estrone-3-O-yl-acyl-Tyr-Arg-OH. Their analgesic activities were investigated using the tail flick test. The potency of the two linkers were significantly higher than that of KTP and the mixture of KTP and hydrocortisone or estrone in the CNS and/or the periphery administration.

Synthesis and thrombolytic activity of pseudopeptides related to fibrinogen fragment

Two kinds of linkers consisting of 3-(S)-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid, ARPAK, GRPAK and QRPAK were synthesized. The thrombolytic activities in vivo indicated that the coupling position of 3-(S)-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid in the peptides effected on the potencies significantly. When the C-terminal of the peptides was amidated by 3-(S)-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid, the thrombolytic potency of the peptides was enhanced or kept. When the N-terminal of the peptides was acylated by 3-(S)-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid, however, the thrombolytic effect of the peptides was banished. The expected specific beta II-turn conformation and the stability to trypsin in the pseudopeptides with 3-(S)-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid in its C-terminal may be responsible for the enhanced thrombolytic potency.

SYNTHESIS OF RGD CONTAINING PEPTIDES AND THEIR BIOACTIVITIES

ABSTRACT RGDS, RGDV, and RGDF were used for the structural modification of YIGSR and YIGSK, the sequences involved in the development of metastasis disease. By use of a solution method, YIGSRRGDS, YIGSRRGDV, YIGSRRGDF, YIGSKRGDS, YIGSKRGDV, YIGSKRGDF, YIGSRYIGSK, and YIGSKYIGSR were prepared in good yield. The results of bioassay in vitro indicated that the target property of RGDS, RGDV, and RGDF to high affinity-receptors may be responsible for the enhanced anti-aggregation, anti-adhesion, and anti-invasion potency.

Stereoselective Transacetalization of 1,1,3,3-Tetramethoxypropane andN-Benzoylaminodiols

The transacetalization of 1,1,3,3-tetramethoxypropane and an N-benzoylaminodiol provided stereoselectively the corresponding 2,5-disubstituted-1,3-dioxanes. The stereochemistry of the rings formed in the transacetalization depended on the structure of the amino diol, and the ratio of the products depended on the reaction conditions, as expected. This kind of stereoselective transacetalization not only gives a series of useful building blocks but also generates interesting 1,3-dioxanes which target protein kinase C.

Synthesis and Thrombolytic Activity of Carboline‐3‐carboxylic Acid Modified Metabolites of Ala‐Arg‐Pro‐Ala‐Lys

Abstract From the metabolism of H‐Ala‐Arg‐Pro‐Ala‐Lys‐OH, four metabolites, H‐Pro‐Ala‐Lys‐OH, H‐Arg‐Pro‐Ala‐Lys‐OH, H‐Ala‐Arg‐Pro‐OH, and H‐Ala‐Arg‐Pro‐Ala‐OH were identified. In order to find a new lead compound of thrombolytic peptide, 3S‐1,2,3,4‐tetrahydro‐β‐carboline‐ 3‐carboxylic acid was introduced to the N‐ and C‐terminal of the metabolites by use of the common coupling strategy. Under this condition, the pseudopeptides (5a–d and 7a–d) were obtained with a good yield. The thrombolytic activities of 3S‐1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylic acid containing oligopeptides were evaluated in vitro and in vivo. The result indicated that the thrombolytic activity of the pseudopeptide depended on the sequence and the modification pattern of the metabolites, and only when 3S‐1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylic acid was introduced into the C‐terminal of H‐Pro‐Aal‐Lys‐OH or H‐Arg‐Pro‐Ala‐Lys‐OH, the desirable thrombolytic activity was retained and enhanced significantly.

Effect of synthetic oligopeptides on osteoporosis.

ABSTRACT The objective of this study was to establish the solution method of GHRPS, the synthetic oligopeptides Tyr-Gly-Gly-Phe-Met-NH2, Tyr-Gly-Gly- Phe-Met-OH, Tyr-Gly-Gly-Phe-Leu-NH2, Tyr-Gly-Gly-Phe-Leu-OH, Tyr-Gly-Gly-Phe-Gly-NH2, and Tyr-Gly-Gly-Phe -Gly-OH, to verify their effect on osteoporosis. Male ICR mice (20±2 g) were used. The intramuscular injection dose of 6.3 mg/kg prednisone induced a significant decrease of body and femur weight of the animals. The subcutaneous injection dose of 18 µg/kg synthetic peptide was not effective to prevent the decrease of body and femur weight of the animals. The subcutaneous injection dose of 6.3 mg/kg prednisone elicited a decrease in content of femur calcium and in the level of serum calcium of the animals. The subcutaneous injection dose of 18 µg/kg Tyr-Gly-Gly-Phe-Leu-NH2, or Tyr-Gly-Gly-Phe-Leu-OH, or Tyr-Gly-Gly-Phe-Gly-NH2 significantly increased the content of femur calcium and decreased the level of serum calcium of the animals. It was also observed that the subcutaneous injection dose of 18 µg/kg Tyr-Gly-Gly-Phe-Gly-OH, Tyr-Gly-Gly-Phe-Leu-OH, Tyr-Gly-Gly-Phe-Met-OH, Tyr-Gly-Gly-Phe-Met-NH2 significantly increased the content of femur phosphorous and decreased the activity of ALP of the animals.

Studies on the Large Scale Synthesis and Anti-tumor Activity of YSL

Abstract H-Tyr-Ser-Leu-OH (YSL), isolated from the degradation products of porcine spleen, was synthesized by a solution method on a large scale via two synthetic strategies. Its structure was confirmed by spectroscopic and related analyses. The in vivo anti-tumor activity was evaluated with murine H22 tumor models. The result indicated that, with the administration of YSL, the survival time of the murine H22 implanted mice was significantly prolonged.

Studies on the synthesis and anti-Osteoporosis of estrogen-GHRPs linkers

The linkers of estrogen-GHRPs were prepared by the combination of estradiol, estrone, TyrGlyGlyPheLeuOH, and TyrGlyGlyPheLeuOH. Their anti-osteoporosis effect was evaluated by analyzing the data, for instance the weight of the body, femur, femur ash, the content of calcium and phosphor in the femur, the content of calcium and ALP activity in the serum, obtained from the corresponding bioassay in vivo. The results indicated that the anti-osteoporosis potency for estradiol, estrone, TyrGlyGlyPheLeuOH and TyrGlyGlyPheLeuNH(2) may be totally enhanced each other via the corresponding linkers.

Synthesis and thrombolytic activity of fibrinogen fragment related cyclopeptides

In the modification of the fibrinogen fragment related sequences ARPAK, QRPAK GRPAK and KRPAK, the corresponding cyclo-ARPAK, cyclo-QRPAK, cyclo-GRPAK, and cyclo-KRPAK were prepared in the diluted solution. The bioassay in vivo indicated that the thrombolytic potencies of cyclo-ARPAK, cyclo-GRPAK, cyclo-QRPAK, and cyclo-KRPAK were significantly higher than that of ARPAK, QRPAK, GRPAK, and KRPAK. In water, the cyclopeptides were incubated with pepsin or trypsin at 37 degrees C for 64 h. There was no degradation product observed, on the other hand, with the same condition, the peptides were completely hydrolyzed in 8 h. The relationships among the rigidity or the conformation and the thrombolytic activity in vivo and the stability to enzyme-induced hydrolysis in vitro of the cyclopeptides were discussed.