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[摘要]：Green tea (Camellia sinensis L.) and Rooibos (Aspalathus linearis Dahlg.) inhibit angiotensin-converting enzyme (ACE) in vitro and in vivo. The ACE inhibitor enalaprilat has been described previously as a competitive inhibitor and sometimes as a non-competitive inhibitor. The aim of this study was to investigate the pharmacological mechanism of ACE inhibition of green tea and Rooibos by enzyme kinetics, and to compare this with enalaprilat. A MichaelisMenten kinetics and LineweaverBurk graph showed mean values of Vmax?=?3.73 mu m and Km?=?0.71 mu m for green tea, of Vmax?=?6.76 mu m and Km?=?0.78 mu m for Rooibos, of Vmax?=?12.54 mu m and Km?=?2.77 mu m for enalaprilat, and of Vmax?=?51.33 mu m and Km?=?9.22 mu m for the PBS control. Incubating serum with green tea or Rooibos saturated with zinc chloride did not change the inhibitory effect. Enalaprilat preincubated with zinc chloride showed a decrease in the inhibitory effect. In conclusion, green tea, Rooibos and enalaprilat seem to inhibit ACE activity using a mixed inhibitor mechanism. Copyright (C) 2011 John Wiley & Sons, Ltd. |
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