Sasagawa T, Oka T, Tokumura A, Nishimoto Y, Muñoz S, Kuwahata M, Okita M, Tsuji H, Natori Y
Department of Nutritional Science, Faculty of Health and Welfare Science, Okayama Prefectural University, Okayama 719-1197, Japan.
Biochim Biophys Acta. 1999 Mar 25;1437(3):317-24. doi: 10.1016/s1388-1981(99)00025-6.
We had previously found that a perchloric acid-soluble protein (PSP1) occurs in rat liver, and that this novel protein inhibits protein synthesis in a rabbit reticulocyte lysate system (T. Oka, H. Tsuji, C. Noda, K. Sakai, Y.-H. Hong, I. Suzuki, S. Muñoz, Y. Natori, J. Biol. Chem. 270 (1995) 30060-30067). In the present study, we analyzed lipid components bound to PSP1. Native PSP1 was purified from rat liver using Sephadex G-75, DE-52 cellulose and IgGPSP-affinity chromatography, and the lipid components were extracted. The components obtained from the purified PSP1 were shown to be free fatty acids by thin-layer chromatography. By GC-MS, six major fatty acids were identified as 14:0, 16:0, 18:0, 18:1, 18:2 and 20:4. 1 mol of PSP1 contained 1.26 mol of total fatty acid components. The fatty acid-binding assay of PSP1 showed that the Bmax was 1.25 mol fatty acid/mol PSP1 and the Kd value for palmitic acid was 6.03 microM. The concentration of PSP1 mRNA in rat liver increased 2.3-fold by the administration of peroxisome proliferator, bezafibrate. These findings show that PSP1 is a fatty acid-binding protein-like protein, which is involved in the intracellular metabolism of fatty acid and is quite different from the known fatty acid-binding proteins.
我们之前发现大鼠肝脏中存在一种高氯酸可溶性蛋白（PSP1），并且这种新型蛋白在兔网织红细胞裂解物系统中抑制蛋白质合成（T. Oka，H. Tsuji，C. Noda，K. Sakai，Y.-H. Hong，I. Suzuki，S. Muñoz，Y. Natori，《生物化学杂志》270 (1995) 30060 - 30067）。在本研究中，我们分析了与PSP1结合的脂质成分。使用葡聚糖凝胶G - 75、DE - 52纤维素和IgGPSP亲和色谱从大鼠肝脏中纯化天然PSP1，并提取脂质成分。通过薄层层析显示，从纯化的PSP1中获得的成分是游离脂肪酸。通过气相色谱 - 质谱联用，鉴定出六种主要脂肪酸为14:0、16:0、18:0、18:1、18:2和20:4。1摩尔PSP1含有1.26摩尔总脂肪酸成分。PSP1的脂肪酸结合测定表明，Bmax为1.25摩尔脂肪酸/摩尔PSP1，棕榈酸的Kd值为6.03微摩尔。通过给予过氧化物酶体增殖剂苯扎贝特，大鼠肝脏中PSP1 mRNA的浓度增加了2.3倍。这些发现表明PSP1是一种类似脂肪酸结合蛋白的蛋白质，它参与脂肪酸的细胞内代谢，并且与已知的脂肪酸结合蛋白有很大不同。
