Fatty acid binding protein: Stimulation of microsomal phosphatidic acid formation
Fatty acid binding protein: Stimulation of microsomal phosphatidic acid formation
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DOI：
10.1006/abbi.1997.9957
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发表时间：
1997-05-01
影响因子：
3.9
通讯作者：
Schroeder, F
中科院分区：
文献类型：
--
作者：
Jolly, CA;Hubbell, T;Schroeder, F
本文研究了脂肪酸结合蛋白（FABPs）对微粒体磷脂酸形成的两个关键步骤的影响。用分子排阻色谱法纯化大鼠肝微粒体，以去除内源性胞浆脂肪酸和脂酰辅酶A结合蛋白，同时使用重组FABPs以避免与来自天然组织的这些蛋白的交叉污染。无论是大鼠肝脏（L-FABP），也没有大鼠肠脂肪酸结合蛋白（I-FABP）刺激肝微粒体脂肪酰辅酶A合成酶。相比之下，L-FABP和I-FABP分别将[C-14]油酰辅酶A和甘油3-磷酸转化为[C-14]磷脂酸的微粒体转化率提高了18倍和7倍。这种刺激的机制，特别是I-FABP，尚不清楚。然而，这里提出的几个观察结果表明，像L-FABP，I-FABP可能与脂肪酰辅酶A相互作用，从而刺激酶的活性。首先，I-FABP减少微粒体膜结合的油酰辅酶A。第二，油酰辅酶A取代I-FABP结合的荧光脂肪酸，顺式-parinaric酸，Ki为5.3 μ M和1.1个位点。第三，油酰辅酶A降低I-FABP色氨酸荧光，Kd为4.2 μ M。第四，丙烯酰化的I-FABP的油酰-CoA红移发射光谱，I-FABP与配体相互作用的灵敏标记物。总之，结果首次证明L-FABP和I-FABP均通过增强脂肪酰辅酶A和甘油3-磷酸合成磷脂酸来刺激肝微粒体磷脂酸形成。(C)北京：科学出版社.
The effect of fatty acid binding proteins (FABPs) on two key steps of microsomal phosphatidic acid formation was examined, Rat liver microsomes were purified by size-exclusion chromatography to remove endogenous cytosolic fatty acid and fatty acyl-CoA binding proteins while recombinant FABPs were used to avoid cross-contamination with such proteins from native tissue. Neither rat liver (L-FABP) nor rat intestinal fatty acid binding protein (I-FABP) stimulated liver microsomal fatty acyl-CoA synthase. In contrast, L-FABP and I-FABP enhanced microsomal conversion of [C-14]oleoyl-CoA and glycerol 3-phosphate to [C-14]phosphatidic acid by 18- and 7-fold, respectively. The mechanism for this stimulation, especially by I-FABP, is not known. However, several observations presented here suggest that, like L-FABP, I-FABP may interact with fatty acyl-CoA and thereby stimulate enzyme activity. First, I-FABP decreased microsomal membrane-bound oleoyl-CoA. Second, oleoyl-CoA displaced I-FABP bound fluorescent fatty acid, cis-parinaric acid, with K-i of 5.3 mu M and 1.1 sites. Third, oleoyl-CoA decreased I-FABP tryptophan fluorescence with a K-d of 4.2 mu M. Fourth, oleoyl-CoA red shifted emission spectra of acrylodated I-FABP, a sensitive marker of I-FABP interactions with ligands. In summary, the results demonstrate for the first time that both L-FABP and I-FABP stimulate liver microsomal phosphatidic acid formation by enhancing synthesis of phosphatidate from fatty acyl-CoA and glycerol 3-phosphate. (C) 1997 Academic Press.