Inhibitory Effects of 5-S-GAD on Phosphorylation of V-SRC and BCR-ABL Tyrosine Kinase

Abstract

We examined the inhibitory effects of N-β-alanyl-5-S-glutathionyl-3, 4-dihydroxyphenylalanine (5-S-GAD), a novel antibacterial substance from the immunized adult Sarcophaga peregrina (flesh fly), on protein phosphorylation using immune complexes of protein tyrosine kinases (PTKs) with anti-PTKs monoclonal antibody. We found that 5-S-GAD directly inhibited not only tyrosine phosphorylation of PTK p60^v-src, but also tyrosine phosphorylation of PTK p210^BCR-ABL. The inhibitory potency of 5-S-GAD was comparable to that of radicicol and herbimycin A of PTK inhibitor.