Abstract
牛蛙的卵母細胞中,核醣核酸脢(RC-RNase)是以游離型及潛伏型兩種型式 同時存在,潛伏型的核醣核酸脢則是與一個核醣核酸脢抑制劑(RCI)複合在 一起.這個RC-RNase-RCI複合物(RC-RNase-RCI complex)可經由陽離子交 換層析法(Phosphocellulose chromatography),硫胺分割,陰離子交換層 析法(DEAE-cellulose chromatography)以及親和性層析法依序純化得 到. 經由凝膠電泳(SDS-PAGE)的分析得知,此核醣核酸脢抑制劑的分子量 大約為110,000道爾吞. 在穩定性方面,60 C 熱處理20分鐘,3M尿素或100 uM p-hydroxymercuribenzoate可使此抑制劑之活性喪失,但二價離子則無 明顯的影響. 我們設立了一個可自RC-RNase-RCI複中純化RCI的方法. 雖 然RCI的活性已喪失,但可作為胺基酸組成及序列的分析之用. There are two forms of RC-RNase, free form and latent form, found in the oocyte of bullfrog (Rana catesbeiana). The latent form of RC-RNase is complexed with an RNase inhibitor (RCI). This RC-RNase-RCI complex was purified to homogeneity by a combination of phosphocellulose chromatography, ammonium sulfate fractionation, DEAE-cellulose chromatography and affinity chromatography. The molecular weight of RCI, estimated by 6% SDS-PAGE,is about 110,000 Daltons. The RCI could be irreversibly activated by heating to 60 C for 20 minutes, 3 M of urea oruM of p-hydroxymercuribenzoate(p-HMB). Further purification of RCI from RC-RNase-RCI complex was tried and discussed.