TRITIATION OF ANILINO GERANYL PYROPHOSPHATE

法尼基化是一种脂质修饰，涉及 通过硫醚键共价加成法呢基类异戊二烯， 胱氨酸残基在或接近某些细胞内的C-末端 proteins. 在过去的几年中，蛋白质的法尼基化已经 与致癌作用的发生密切相关， Ras癌基因 焦磷酸法呢酯（FPP）由 酶蛋白-法尼基转移酶（PFT酶）作为这种酶的来源， 法呢基部分。 我们描述了一个法呢基的设计和合成， 焦磷酸类似物，8-苯胺-香叶基焦磷酸（AGPP）。 我们 已经用苯胺取代了FPP的W-末端异戊二烯单元 功能. AGPP的类异戊二烯碳链几乎为 可与FPP重叠。 AGPP是PFTase的底物， 作为天然底物。 我们还描述了合成 使用3 H-乙酰氧基硼三氢化钠通过还原胺化得到3 H-AGPP。 3 H-AGPP通过PFTase以与PFTase相同的动力学转移至Ras。 天然底物FPP。 存在AGPP浓度依赖性 在对应于Ras的蛋白质条带中出现3 H SDS-PAGE凝胶上的蛋白质。 AGPP或FPP，但AGOH或法尼醇不能 抑制这种浓度依赖性。 该酶的Km值为 AGPP与FPP（0.13 mM）相比是有利的。 研究将 继续使用氚化AGPP和FPP的其他光不稳定类似物， 阐明法尼基化的机制和 致癌作用

Farnesylation is a type of lipid modification involving the covalent addition of a farnesyl isoprenoid via a thioether linkage to cystine residues at or near the C-terminus of certain intracellular proteins. In the past several years farnesylation of proteins has been strongly linked to the onset of carcinogenesis attributable to the Ras oncogene. Farnesyl pyrophosphate (FPP) is utilized by the enzyme protein-farnesyl transferase (PFTase) as the source of this farnesyl moiety. We describe the design and synthesis of a farnesyl pyrophosphate analogue, 8-aniline-geranyl pyrophosphate (AGPP). We have replaced the w-terminal isoprene unit of FPP with an aniline functionality. The carbon isoprenoid chain of AGPP is nearly superimposable with FPP. AGPP is a substrate for PFTase and is as active as the natural substrate. We also describe the synthesis of 3H-AGPP via reductive amination using 3H-sodium acetoxyborotritide. 3H-AGPP is transferred to Ras by PFTase with the same kinetics as the natural substrate FPP. There is a AGPP concentration dependent appearance of 3H in the protein band that corresponds to the Ras protein on SDS-PAGE gel. AGPP or FPP, but not AGOH or farnesol can inhibit this concentration dependence. The Km value of the enzyme for AGPP compares favorably with that for FPP (0.13 mM). Studies will continue with tritiated AGPP and other photolabile analogs of FPP to elucidate the mechaisms of farnesylation and the early stages of carcinogenesis.