一种来自酵母的与40 S核糖体亚基相关的核糖核酸酶。

A ribonuclease from yeast associated with the 40 S ribosomal subunit.

Schulz-Harder B, Käufer N, Swida U

Biochim Biophys Acta. 1979 Nov 22;565(1):173-82. doi: 10.1016/0005-2787(79)90093-5.

Abstract

Autodegradation of yeast ribosomes is due to a 'latent' ribonuclease which is associated with the 40 S ribosomal subunit. 2. The ribonuclease was extracted in the presence of EDTA from ribosomes and purified 118-rold by protamine sulphate precipitation, (NH4)2SO4 fractionation and chromatography on DEAE-cellulose. 3. The optimum pH for this enzyme is 5 to 6.5 while the optimum temperature is 45 to 50 degrees C. Incubation for 10 min at 60 degrees C caused a reduction in enzyme activity of 70%. 4. The ribonuclease has an endonucleolytic activity against rRNA, tRNA, poly(A), poly(U) and poly(C) but does not degrade poly(G) or DNA. It hydrolyzes the homopolymers to nucleoside 3'-phosphates. 5. Zn2+, Mn2+, heparin, glutathione and p-chloromercuribenzoate inhibit the ribonuclease, while Na+, K+, EDTA and sermidine have only little or no effect. 6. It binds tightly to yeast ribosomes but only loosely to ribonuclease-free wheat germ ribosomes. 7. Polyribosomes possess less autodegradation activity than monoribosomes, isolated from the same homogenate.

摘要

酵母核糖体的自降解是由于一种与40S核糖体亚基相关的“潜在”核糖核酸酶。2. 在EDTA存在的情况下从核糖体中提取核糖核酸酶，并通过硫酸鱼精蛋白沉淀、硫酸铵分级分离和DEAE - 纤维素柱层析将其纯化118倍。3. 该酶的最适pH为5至6.5，最适温度为45至50摄氏度。在60摄氏度下孵育10分钟会导致酶活性降低70%。4. 该核糖核酸酶对rRNA、tRNA、聚腺苷酸、聚尿苷酸和聚胞苷酸具有内切核酸酶活性，但不降解聚鸟苷酸或DNA。它将这些同聚物水解为核苷3'-磷酸。5. Zn2+、Mn2+、肝素、谷胱甘肽和对氯汞苯甲酸抑制该核糖核酸酶，而Na+、K+、EDTA和精脒只有很小的影响或没有影响。6. 它与酵母核糖体紧密结合，但与不含核糖核酸酶的小麦胚芽核糖体结合较松散。7. 从同一匀浆中分离得到的多核糖体比单核糖体具有更低的自降解活性。