J. Biol. Chem., Vol. 255, Issue 11, 5108-5112, 06, 1980
Isolation and characterization of the novel polyadenylate- and polyuridylate-degrading acid endoribonuclease V from calf thymus
HC Schroder, K Dose, RK Zahn and WE Muller
A novel endoribonuclease was detected and purified to homogeneity from calf
thymus. The homogeneity was checked by analysis in polyacrylamide gels
(both in the presence and in the absence of sodium dodecyl sulfate) as well
as by isoelectric focusing. This nuclease activity, which is called
Endoribonuclease V, cleaves poly(A) and poly(U); other single- or
double-stranded synthetic polyribo- as well as polydeoxyribonucleotides are
not degraded. Endoribonuclease V cleaves poly(A) to create first
oligoribonucleotides and ultimately 3'-AMP; no P-2':3'-Ado degradation
products were detected. The enzyme has a pH optimum of 5.8, an isoelectric
point of pH 6.3, a molecular weight of 52,300, and requires neither
monovalent nor divalent cations. The enzyme activity is not inhibited by
N-ethylmaleimide.