[Purification and properties of ribonuclease from the eggs and embryos of the loach Misgurnus fossilis].

Endo- and exoribonucleases from loach eggs and embryos were partially purified. Endoribonuclease from loach embryos has a pH optimum of 8.4, is thermostable, has a molecular weight of about 37 000, requires Ca2+ for its activity, rapidly splits poly-U and slowly splits poly-C and does not hydrolyze poly-A. Exoribonuclease has a pH optimum of 7.6 and is relatively thermostable; its activity is independent of Ca2+, it has a molecular weight of 12 000, preferentially hydrolyzes RNA of yeast and poly-U, rather slowly hydrolyzes poly-C and does not split poly-A. The properties of the tested enzymes from loach embryos at early organogenesis do not differ from those of the enzymes from unfertilized eggs.