Abstract

The ginsenoside Re is the major ingredient of ginsenosides, which was isolated from ginseng (genus Panax). The purpose of the study is to investigate into the effect of ginsenoside Re on Mg²⁺-ATPase activity of smooth muscle myosin and phosphorylation of myosin light chain by myosin light chain kinase (MLCK), and try to find out the regular pattern resulting from ginsenoside Re on myosin function. Myosin and MLCK used in our study were purified from the chicken gizzard smooth muscle. Myosin phorphorylation was determined by glycerol polyacrylamide gel electrophoresis (PAGE). Myosin Mg²⁺-ATPase activity was measured by Pi liberation method. The results showed that ginsenoside Re stimulates Mg²⁺-ATPase activities, promotes phosphorylation of partially phosphorylated myosin, inhibits Mg²⁺-ATPase activity and decrease phosphorylation of fully phosphorylated myosin in a dose dependent manner and in a time dependent manner. The findings demonstrated that the use of ginsenoside Re on various states of myosin phosphorylation produced different responses in a purified incubation system.

Key words: Ginsenoside Re, myosin phosphorylation, myosin Mg²⁺-ATPase activity, bi-directional regulation.

Abbreviation

CDPM, Ca²⁺-calmodulin dependent phosphorylation of myosin light chains;MLCK, myosin light chain kinase; PAGE, polyacrylamide gel electrophoresis; MLC₂₀, 20 kDa myosin regulating light chain; LC₂₀, unphosphorylated MLC₂₀; p-LC₂₀, mono-phosphorylated MLC₂₀; LC₁₇, 17 kDa myosin essential light chains.