Barile M, Valenti D, Brizio C, Quagliariello E, Passarella S
Dipartimento di Biochimica e Biologia Molecolare, Università di Bari, Italy.
FEBS Lett. 1998 Sep 11;435(1):6-10. doi: 10.1016/s0014-5793(98)01007-2.
We show here that TPP --> TMP conversion can take place in rat liver mitochondria. This occurs via the novel, putative TPP pyrophosphatase localised in the mitochondrial matrix, as shown both by digitonin titration and by an HPLC enzyme assay carried out on the mitochondrial matrix fraction. Certain features of the reaction, including the substrate and pH dependence, are reported. Additional evidence is given that externally added TMP can cross the mitochondrial membrane in a manner consistent with the occurrence of a carrier-mediated process. This can occur both via the TPP translocator and via a novel translocator, inhibited by CAT but different from the ADP/ATP carrier.
我们在此表明，TPP向TMP的转化可在大鼠肝线粒体中发生。这是通过定位于线粒体基质中的新型假定TPP焦磷酸酶实现的，洋地黄皂苷滴定法和对线粒体基质部分进行的HPLC酶分析均证明了这一点。报告了该反应的某些特征，包括对底物和pH的依赖性。此外，有证据表明，外部添加的TMP能够以与载体介导过程相符的方式穿过线粒体膜。这既可以通过TPP转运体发生，也可以通过一种新型转运体发生，该转运体受CAT抑制，但不同于ADP/ATP载体。
