Penttilä K E, Mäenpää P H
J Steroid Biochem. 1985 Apr;22(4):559-61. doi: 10.1016/0022-4731(85)90178-5.
The ribonuclease activity associated with rooster liver ribosomes decreases and the endogenous ribosomal RNAase inhibitor becomes undetectable during estrogen-induced vitellogenin synthesis. The RNAase-catalyzed autodegradation of ribosomes in vitro is inhibited by Mg2+ and spermidine, while EDTA in low concentrations has an activating effect. Single-stranded, uridylic acid containing ribonucleotide polymers are the best substrates for the enzyme. Of the four homopolyribonucleotides, ribosomal RNAase catalyzes the degradation of poly(U), poly(A), and poly(C) in decreasing order of reactivity, while poly(G) is not degraded. Ribosomal RNAases from control and estrogen-stimulated roosters show differences in response to Mg2+, spermidine and EDTA. In addition, the reactivities of poly(U) and poly(C) as substrates using RNAases from stimulated roosters are markedly different from those obtained with the enzymes from control roosters.
在雌激素诱导的卵黄蛋白原合成过程中，与公鸡肝脏核糖体相关的核糖核酸酶活性降低，内源性核糖体核糖核酸酶抑制剂变得无法检测到。体外核糖体的核糖核酸酶催化的自降解受到Mg2+和亚精胺的抑制，而低浓度的EDTA具有激活作用。含尿苷酸的单链核糖核苷酸聚合物是该酶的最佳底物。在四种同聚核糖核苷酸中，核糖体核糖核酸酶催化多聚尿苷酸（poly(U)）、多聚腺苷酸（poly(A)）和多聚胞苷酸（poly(C)）的降解，其反应活性依次降低，而多聚鸟苷酸（poly(G)）不被降解。来自对照公鸡和雌激素刺激公鸡的核糖体核糖核酸酶对Mg2+、亚精胺和EDTA的反应存在差异。此外，使用来自刺激公鸡的核糖核酸酶时，多聚尿苷酸（poly(U)）和多聚胞苷酸（poly(C)）作为底物的反应活性与来自对照公鸡的酶所获得的反应活性明显不同。
