신규 항균물질 5-S-GAD(N-beta-alanyl-5-S-glutathionyl-3,4-dihydroxyphenylalanine)의 합성 및 생리활성

Synthesis and Biological Activity of 5-S-GAD(N-brta-alanyl-5-S-glutathionyl-3,4-dihydroxyphenylalanine), a Novel Antibacterial Substance

We had already reported that we purified N-beta-alanyl-5-S-glutathionyl-3,4-dihydroxyphenylalanine (5-S-GAD), a novel antibacterial substance from the immunized adult Sarcophaga peregrina (Flesh fly). We found that the antibacterial activity of synthetic 5-S-GAD is equal to that of authentic 5-S-GAD without a specificity of antibacterial activity against Gram positive and Gram negative. Significant synergism was detected between 5-S-GAD and streptomycin against streptomycin resistant strain E.coli K12 594. It has an antitumor activity against several tumor cell lines at a concentration of 100mcM. However, no cytotoxic activity against murine macrophage was detected at a concentration of 500mcM. Furthermore, haemolytic activity against sheep erythrocytes was not detected at the same concentration. We suggest that the S-conjugation of glutathion with dihydroxyphenylalanine might be important to increase antibacterial activity of dihydroxyphenylalanme.