HELICOBACTER-PYLORI CATALASE
HELICOBACTER-PYLORI CATALASE
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DOI：
10.1099/00221287-137-1-57
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发表时间：
1991-01-01
期刊：
影响因子：
--
通讯作者：
GRAHAM, DY
中科院分区：
文献类型：
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作者：
HAZELL, SL;EVANS, DJ;GRAHAM, DY
幽门螺杆菌是人类胃十二指肠炎的主要病原。由于过氧化氢酶在炎症粘膜表面幽门螺杆菌的生长和存活中具有潜在的重要性，我们对幽门螺杆菌中的过氧化氢酶进行了表征，为进一步研究该酶在体内的功能做了铺垫。生长培养基中存在血液、血清或红细胞对幽门螺杆菌过氧化氢酶活性有显著影响，在含有血清的培养基中生长时活性最高。幽门螺杆菌过氧化氢酶是一种亚基M(r)为50000的四聚体。该酶的pI为9.0-9.3，在较宽的pH范围内具有活性，在56℃时稳定。叠氮化钠对其无竞争性抑制作用，且无过氧化物酶活性。过氧化氢酶的K(m)为43 +/- 3 mM-H2O2， V为60 +/- 3 mmol H2O2 min-1 （mg蛋白）-1。天然过氧化氢酶在280 nm和405 nm处具有最大吸收，在510 nm、535 nm和625 nm处有较小的肩部或峰，与铁卟啉假基的存在一致。
Helicobacter pylori is the major aetiological agent of gastroduodenitis in humans. Due to the potential importance of catalase in the growth and survival of Helicobacter pylori on the surface of inflamed mucosae, we have characterized catalase from H. pylori as a prelude to further studies on the function of the enzyme in vivo. The catalase activity of H. pylori was significantly affected by the presence of blood, serum or erythrocytes in the growth medium: the greatest activity was expressed when the bacterium was grown on medium containing serum. H. pylori catalase is a tetramer with a subunit M(r) of 50 000. The enzyme had a pI of 9.0-9.3, was active over a broad pH range and was stable at 56-degrees-C. It was non-competitively inhibited by sodium azide, and had no detectable peroxidase activity. The K(m) for the purified catalase was measured as 43 +/- 3 mM-H2O2 and the V as 60 +/- 3 mmol H2O2 min-1 (mg protein)-1. The native catalase has absorption maxima at 280 nm and 405 nm with further minor shoulders or peaks at 510 nm, 535 nm and 625 nm, consistent with the presence of an iron-porphyrin prosthetic group.