Purification and characterization of a 100 kDa glycyrrhizin (GL)-binding protein (gp100) as an effective phosphate acceptor for CK-II and the effect of GL on the phosphorylation of gp100 by CK-II in vitro

Abstract

By means of successive GL-affinity and Mono S column chromatographies (HPLC), a 100 kDa GL-binding protein (gp100) was purified from the partially purified CK-II fraction of EAT cells as an effective phosphate acceptor for CK-II. It was found that (i) gp100 (pI 9.0) is copurified with CK-II, Hsp-90 and p34 or p70; (ii) gp100 cross-reacts with anti-human GR; (iii) phosphorylation of gp100 by CK-II is significantly stimulated by 1 microM GL or 0.3 microM oGA; and (iv) GL as well as DEX inhibit it at doses above 3 microM. Data are provided to suggest that the GL-induced selective inhibition of the CK-II catalyzed phosphorylation of gp100 may be involved in the anti-inflammatory effects of GL.