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B6db references: 17981822.b

type Journal Article
authors Kong Y, Wu D, Bai H, Han C, Chen J, Chen L, Hu L, Jiang H, Shen X.
title Enzymatic characterization and inhibitor discovery of a new cystathionine {gamma}-synthase from Helicobacter pylori
journal J Biochem
Activity 2.5.1.48
sel selected
ui 17981822 b
year (2008)
volume 143
number 1
pages 59-68
 
keywords Amino Acid Sequence
abstract Cystathionine gamma-synthase (CGS) catalyses the first step of the transsulfuration pathway that converts l-cysteine to l-homocysteine in bacteria, whereas this pathway is absent in human. In this report, we identified a new metB gene from Helicobacter pylori strain SS1, and the recombinant H. pylori Cystathionine gamma-synthase (HpCGS) was successfully cloned, expressed and purified in Escherichia coli system. Enzymatic study of HpCGS indicated that the K(m) and k(cat)/K(m) values against the substrate O-succinyl-l-homoserine (l-OSHS) were 3.02 mM and 98.7 M(-)(1)s(-)(1), respectively. Moreover, four natural products (alpha-lapachone, 9-hydroxy-alpha-lapachone, Paulownin and Yangambin, Fig. 1) were discovered to demonstrate inhibitory activities against HpCGS with IC(50) values of 11 +/- 3, 9 +/- 1, 19 +/- 2 and 27 +/- 6 microM, respectively. All these four inhibitors prevent the binding of l-OSHS to HpCGS in a non-competitive fashion. In vitro antibacterial assays further indicated that these four discovered compounds could highly inhibit the growth of H. pylori and exhibited strong inhibitory specificity against H. pylori related to E. coli.
last changed 2010/01/28 11:35

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