Gbenle G O, Akinrimisi E O
Mol Biochem Parasitol. 1982 Apr;5(4):213-20. doi: 10.1016/0166-6851(82)90030-5.
A calcium-dependent endoribonuclease isolated from Trypanosoma brucei cytoplasm has been further characterized. The products of exhaustive endonuclease digestion of poly(A), which the enzyme cleaved preferentially, were small oligonucleotides terminated by a 5'-phosphoryl group. Its apparent Km value was 0.8 mM using poly (A), and 3.3 mM using transfer RNA. The base specificity of the endoribonuclease was further verified by using synthetic heteropolyribonucleotides as substrates. The enzymatic reaction was inhibited by polyamines, polyanions, iodoacetic acid and the heavy metals, but only very slightly by N-ethylmaleimide and iodoacetamide. A possible implication of the enzyme in the turnover of messenger RNA is discussed.
从布氏锥虫细胞质中分离出的一种钙依赖性核糖核酸内切酶已得到进一步鉴定。该酶优先切割的聚腺苷酸（poly(A)）经核酸内切酶彻底消化后的产物是由5'-磷酸基团终止的小寡核苷酸。以聚腺苷酸为底物时，其表观米氏常数（Km）值为0.8 mM，以转运核糖核酸（tRNA）为底物时为3.3 mM。通过使用合成杂聚核糖核苷酸作为底物，进一步验证了该核糖核酸内切酶的碱基特异性。该酶促反应受到多胺、聚阴离子、碘乙酸和重金属的抑制，但仅受到N-乙基马来酰亚胺和碘乙酰胺的轻微抑制。文中讨论了该酶在信使核糖核酸（mRNA）周转中的可能作用。
