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Laura Landi Petronio Pasquali Luciana Cabrini Anna Maria Sechi Giorgio Lenaz 《Journal of bioenergetics and biomembranes》1984,16(2):153-166
The combined effects of rotenone and ubiquinone-3 on the kinetics of NADH dehydrogenase and NADH oxidase have been investigated. The two inhibitors do not show additivity; on the other hand, ubiquinone-3, when preincubated with the enzyme, partially removes rotenone sensitivity. The inhibition of NADH oxidase by ubiquinone-3 is the result of at least two combined effects: the competition of the less active ubiquinone-3 with endogenous ubiquinone-10 in the acceptor site of the dehydrogenase, and a nonspecific action on the structure of complex I. The latter effect is perhaps mediated by a physical change of the phospholipid bilayer similar to that observed with agents such as butanol, perturbing lipid-protein interactions in the membrane. 相似文献
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Chromosome 11p15 deletions in human malignant astrocytomas and primitive neuroectodermal tumors. 总被引:4,自引:0,他引:4
Chromosome 11p15 deletions occur frequently in several types of human cancer, both sporadic and familial, suggesting that a tumor suppressor gene is present within the deleted chromosome region. We carried out a restriction fragment length polymorphism analysis of chromosome 11p in two types of human brain tumors: malignant astrocytoma, the most common glial tumor in adults; and primitive neuroectodermal tumor (PNET), a malignant embryonic tumor that afflicts children. Loss of heterozygosity was found in 11/43 malignant astrocytomas (26%) and in 3/11 PNETs (27%). Deletion mapping revealed a region of loss on chromosome 11p (p15.4-pter) that was common to both tumor types. To determine whether the c-H-ras gene, located on chromosome 11p in the common region of deletion, was a candidate gene, we analyzed polymerase chain reaction products corresponding to all four c-H-ras coding exons for single-strand conformation polymorphisms. The absence of electrophoretic mobility shifts in tumor DNA compared to leukocyte DNA indicated that c-H-ras gene mutations were most likely not present. These results suggested that loss of a gene on chromosome 11p15 distinct from c-H-ras is an important step in tumorigenesis within the central nervous system in both children and adults. 相似文献