Acetyl-CoA carboxylase activity in Helicobacter pylori and the requirement of increased CO2 for growth

被引:34
作者
Burns, BP
Hazell, SL
Mendz, GL
机构
[1] UNIV NEW S WALES,SCH MICROBIOL & IMMUNOL,SYDNEY,NSW 2052,AUSTRALIA
[2] UNIV NEW S WALES,SCH BIOCHEM & MOLEC GENET,SYDNEY,NSW 2052,AUSTRALIA
来源
MICROBIOLOGY-UK | 1995年 / 141卷
关键词
Helicobacter pylori; acetyl-CoA carboxylase; CO2;
D O I
10.1099/13500872-141-12-3113
中图分类号
Q93 [微生物学];
学科分类号
071005 ; 100705 ;
摘要
A biotinylated acetyl-CoA carboxylase from the microaerophilic bacterium Helicobacter pylori was partially purified and characterized. The approximate molecular mass of the native enzyme was estimated at 235 kDa by native PAGE. A single band corresponding to approximately 24 kDa was detected by SDS-PAGE, suggesting that the native enzyme is a multi-protein complex. The protein was isolated from the soluble fraction of the cell. Catalytic activity was acetyl-CoA-dependent and inhibited by avidin but unaffected by avidin pretreated with excess biotin. The end-product of the reaction was identified as malonyl-CoA and the reaction was shown to be reversible by NMR spectroscopy. The activity of the enzyme was 0.29 mu mol min(-1) (mg protein)(-1). The V-max for bicarbonate was calculated at 0.73 mu mol min(-1) (mg protein)(-1), and the affinity of the enzyme for this substrate was relatively low, with an apparent K-m of 16.6 mM. These data provide the first evidence of a possible physiological role for the requirement of high levels of CO2 for growth in vitro of this bacterium.
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页码:3113 / 3118
页数:6
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