Isolation of a novel thermolabile heterodimeric ribonuclease with antifungal and antiproliferative activities from roots of the sanchi ginseng Panax notoginseng.

An isolation procedure, consisting of ion exchange chromatography on CM-Sepharose, affinity chromatography on Affi-gel blue gel, and fast protein liquid chromatography on Mono S, was utilized to purify a base-nonspecific, heterodimeric ribonuclease (RNase) with diverse activities from roots of the sanchi ginseng Panax notoginseng. The RNase is unique in that it consists of two different nonglycoprotein subunits with a molecular weight of 27 and 29 kDa, respectively. The latter subunit is characterized by an N-terminal sequence showing remarkable similarity to that of the bitter gourd RNase. The Panax notoginseng RNase demonstrates potent RNase and translation-inhibitory activities. In addition, it exhibits antiproliferative activity toward leukemia L1210 cells and antifungal activity against Physalospora piricola and Coprinus comatus. Its RNase activity is not heat-resistant, unlike most RNases which are thermostable.