精胺酸甲基轉化酶2（Arginine methyltransferase 2, RMT2）在酵母菌中被分類為第四型的精胺酸甲基轉化酶。此蛋白質表現在大腸桿菌並藉由陰離子交換樹脂純化。由膠體過濾管柱色層分析法分析可估計此重組RMT2蛋白質分子量為47 kDa，由此可知重組RMT2蛋白質主要以單體的形式存在。將重組RMT2蛋白質加至酵母菌野生種細胞分解液中反應，並利用Superose 6膠體過濾管柱色層分析法分析，由分離出來的位置得知RMT2是以複合體的型式存在。此複合體經過DNaseⅠ、RNase A 處理後，並不會影響RMT2蛋白質在膠體過濾管柱分離出來的位置。本篇論文利用專一性的RMT2抗體交叉聯結蛋白質A-膠體來純化酵母菌野生種細胞分解液。在對照組方面，選擇使用RMT2缺乏突變種細胞分解液來做相同的實驗步驟。利用一維膠體電泳分離與RMT2有相互作用之蛋白質，經胰蛋白酶消化後之胜肽則送至基質輔助雷射脫附游離飛行時間式質譜儀(matrix-assisted laser desorption/ionization time-of-flight, MALDI-TOF)中分析。經由質譜儀分析所得的胜肽圖譜，利用MASCOT程式送至NCBI資料庫做比對，鑒別出與RMT2相互作用的蛋白質。我們找到Ssa2p，Ssb1p、Cdc19p、Pdc1p、Tef2p、Eno2p、Pgk1p、Adh1p、Fba1p、Tdh3p及Tdh2p等十一個蛋白質會和RMT2相互作用。

Type Ⅳ protein arginine methyltransferase （RMT2） from the yeast Saccharomyces cerevisiae was expressed in Escherichia coli and purified by ion-exchange chromatography. The recombinant RMT2 at is apparently in monomeric form and has a molecular mass of 47 kDa as determined by gel exclusion chromatography. The recombinant protein was incubated with cell extracts from a wild type yeast strain then further separated on the Superose 6 column. RMT2 thus recovered has an elution volume suggesting the existence of a complex. The recovered recombinant RMT2 and the associated proteins were treated with DNase I and RNase A, and then further separated on the same column. The recombinant RMT2 still has the same retention time on the Superose 6 column. The putative RMT2 complex was purified from wild type yeast extracts with RMT2 specific antibodies coupled onto protein A-agarose beads. As controls, similar experiments were carried out with extracts from a RMT2 deletion strain. Proteins that are possibly associated or interacted with RMT2 were separated with 1-D SDS-PAGE and identified by peptide mapping on a time-of-flight mass spectrometer equipped with a MALDI source. Proteins identified include: Saa2p, Ssb1p, Cdc19p, Pdc1p, Tef2p, Eno2p, Pgk1p, Adh1p, Fba1p, Tdh3p and Tdh2p.

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