Storch J, Bass N M
Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts 02115.
J Biol Chem. 1990 May 15;265(14):7827-31.
Fatty acid binding proteins (FABP) are a family of 14-15 kDa proteins found in high abundance in many mammalian cell types. The physiological functions of the FABP remain unknown. It is also not known whether each FABP has a unique function, or whether all FABP function in a similar manner in their respective tissues. In this report the rate of transfer of anthroyloxy-labeled free fatty acid (ffa) from FABP to phospholipid bilayers is monitored using a fluorescence resonance energy transfer assay. A comparison is made between heart muscle FABP and liver FABP, and the results show that the rate of ffa transfer from the heart protein is an order of magnitude greater than the rate of transfer from the liver protein. Ffa transfer rates from both liver and heart FABP are independent of acceptor concentration and composition, suggesting that, at least in the case of model membrane acceptor vesicles, the mechanism of transfer is via aqueous diffusion rather than via collision of FABP with membranes. Since the rate of ffa transfer is likely to be important to cellular ffa traffic, these studies suggest that heart FABP may function differently within the myocyte than does liver FABP within the hepatocyte.
脂肪酸结合蛋白（FABP）是一类分子量为14 - 15 kDa的蛋白质家族，在许多哺乳动物细胞类型中大量存在。FABP的生理功能尚不清楚。目前也不清楚每种FABP是否具有独特功能，或者所有FABP在各自组织中是否以相似方式发挥作用。在本报告中，使用荧光共振能量转移测定法监测了蒽氧基标记的游离脂肪酸（ffa）从FABP向磷脂双层的转移速率。对心肌FABP和肝脏FABP进行了比较，结果表明，ffa从心脏蛋白的转移速率比从肝脏蛋白的转移速率高一个数量级。肝脏和心脏FABP的ffa转移速率均与受体浓度和组成无关，这表明，至少在模型膜受体囊泡的情况下，转移机制是通过水相扩散，而不是通过FABP与膜的碰撞。由于ffa转移速率可能对细胞内ffa运输很重要，这些研究表明心脏FABP在心肌细胞内的功能可能与肝脏FABP在肝细胞内的功能不同。
