Fraser F, Zammit V A
Hannah Research Institute, Ayr, Scotland KA6 5HL, U.K.
Biochem J. 1998 Jan 15;329 ( Pt 2)(Pt 2):225-9. doi: 10.1042/bj3290225.
The submitochondrial distribution of the overt and latent carnitine palmitoyltransferases (CPT I and II respectively) of rat liver mitochondria were studied. Separation of outer and inner membranes, as well as of a fraction of intermediate density consisting of contact sites between the two membranes, was achieved, as judged by the distribution of marker enzymes. Both CPT I and CPT II were found to be enriched within the contact- site fraction of mitochondria. These data show that the two carnitine acyltransferases are distributed non-uniformly within their respective membranes, and that subpopulations of the two enzymes occur in close proximity within the mitochondrial membrane structure, while retaining their different accessibilities to cytosolic and matrix pools of metabolites. As the number of contact sites is known to vary with changes in the energy status of mitochondria, the possibility that such changes may acutely affect the proportion of CPT I within the distinctive lipid environment of the contact sites, and thus its overall kinetic characteristics, is discussed.
研究了大鼠肝脏线粒体中显性和隐性肉碱棕榈酰转移酶（分别为CPT I和CPT II）的亚线粒体分布。通过标记酶的分布判断，实现了外膜和内膜以及由两层膜之间的接触位点组成的部分中等密度组分的分离。发现CPT I和CPT II均在线粒体的接触位点组分中富集。这些数据表明，这两种肉碱酰基转移酶在各自的膜内分布不均匀，并且这两种酶的亚群在线粒体膜结构中紧密相邻，同时保持它们对代谢物的胞质和基质池的不同可及性。由于已知接触位点的数量会随着线粒体能量状态的变化而变化，因此讨论了这种变化可能会急性影响接触位点独特脂质环境中CPT I的比例，进而影响其整体动力学特性的可能性。
