THE FLAVIN-CONTAINING MONOOXYGENASE IN MOUSE LUNG - EVIDENCE FOR EXPRESSION OF MULTIPLE FORMS

被引:7
|
作者
VENKATESH, K
BLAKE, B
LEVI, PE
HODGSON, E
机构
[1] Department of Toxicology, North Carolina State University, Raleigh, North Carolina
来源
JOURNAL OF BIOCHEMICAL TOXICOLOGY | 1992年 / 7卷 / 03期
关键词
D O I
10.1002/jbt.2570070305
中图分类号
R99 [毒物学(毒理学)];
学科分类号
100405 ;
摘要
The flavin-containing monooxygenase (FMO) was purified from mouse lung microsomes. On SDS-PAGE, the purified enzyme separated as two bands, a major band of 58,000 daltons and a minor band of 59,000 daltons. Antibodies to mouse liver FMO cross-reacted with both bands in the purified preparations, whereas antibodies to rabbit lung FMO cross-reacted only with the major band. In microsomal preparations the major band was recognized by both antibodies, but neither antibody detected the minor band in microsomes. A cDNA encoding the pig liver FMO hybridized with mRNA isolated from mouse liver, kidney, and lung, whereas cDNA encoding the rabbit lung FMO hybridized only with mouse lung and kidney mRNA. Thermal stability studies showed that the FMO preparation purified from mouse lung consisted of a heat-stable and a heat-labile component. The heat-labile component of lung FMO was inhibited competitively by imipramine, whereas the heat-stable component was insensitive to the presence of imipramine. Immunoprecipitation of purified mouse lung FMO with anti-rabbit lung FMO completely removed the protein band reactive to anti-rabbit lung FMO while leaving reactivity to anti-liver FMO. The catalytic and immunochemical differences seen between FMO from rabbit lung and mouse lung appear to result from the expression of at least two forms of FMO in the mouse lung, one similar to the rabbit pulmonary form and one similar to the major mouse liver form of FMO.
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页码:163 / 169
页数:7
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