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http://ir.cmu.edu.tw/ir/handle/310903500/30920
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| 題名: | Inhibition of nitric oxide synthase expression by PPM-18, a novel anti-inflammatory agent, in vitro and in vivo |
| 作者: | Yu, SM;Wu, JF;Lin, TL;Kuo, SC |
| 貢獻者: | 藥學院藥化所;CHINA MED COLL,INST PHARMACEUT CHEM,TAICHUNG,TAIWAN |
| 日期: | 1997 |
| 上傳時間: | 2010-09-24 15:06:22 (UTC+8) |
| 出版者: | PORTLAND PRESS |
| 摘要: | Glycyrrhizic acid, one of the proposed chemopreventive drugs, was used to inhibit arylamine N-acetyltransferase (NAT) activity in Klebsiella pneumoniae, both in cytosol and intact bacteria. The NAT activity was measured by using high-performance liquid chromatography to assay the amounts of 2-acetyl-aminofluorene and remaining 2-aminofluorene. The NAT activity in K, pneumoniae was inhibited by glycyrrhizic acid in a dose-dependent manner, The cytosol NAT activities were 0.675 +/- 0.028 nmol min(-1) mg(-1) protein for the acetylation of 2-aminofluorene without glycyrrhizic acid and 0.367 +/- 0.008 nmol min(-1) mg(-1) protein with 8 mM glycyrrhizic acid, The NAT activities measured from intact bacteria were 0.308 +/- 0.018 nmol min(-1) 10(-10) colony forming units for the acetylation of 2-aminofluorene without glycyrrhizic acid and 0.236 +/- 0.005 nmol min(-1) 10(-10) colony forming units in the presence of 8 mM glycyrrhizic acid, The inhibition of NAT activity by glycyrrhizic acid was demonstrated to remain for at least 4h, The apparent K-m and V-max values calculated from cytosol NAT were 1.08 +/- 0.05 mM and 9.09 +/- 0.11 nmol min(-1) mg(-1) protein, respectively, for 2-aminofluorene. In the presence of 8 mM glycyrrhizic acid, the apparent K-m and V-max values were 0.15 +/- 0.01 mM and 0.95 +/- 0.11 nmol min(-1) mg(-1) protein, respectively, for 2-aminofluorene. In intact bacteria, the apparent K-m and V-max values were 1.28 +/- 0.48 mM and 4.08 +/- 1.06 nmol min(-1) 10(-10) colony forming units, respectively, for 2-aminofluorene. However, in the presence of 8 mM glycyrrhizic acid, the apparent K-m and V-max values were 0.67 +/- 0.09 mM and 1.82 +/- 0.37 nmol min(-1) 10(-10) colony forming units, respectively, for 2-aminofluorene. Taking these results together, the NAT activity in K, pneumoniae was inhibited by glycyrrhizic acid both in cytosol and intact bacteria, This study provides the first evidence to demonstrate that glycyrrhizic acid inhibits bacterial NAT activity. (C) 1997 by John Wiley & Sons, Ltd. |
| 關聯: | BIOCHEMICAL JOURNAL 328():363-369 |
| 顯示於類別: | [藥物化學研究所] 期刊論文
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