흰쥐 腦組織에서 部分精製한 알칼리 性 Ribonuclease와 그 Natural Inhibitor 에 관한 研究

ON PARTIAL PURIFICATION AND PROPERTIES OF ALKALINE RIBONUCLEASE AND ITS NATURAL INHIHIBITOR FROM ALBINORAT BRAIN TISSUE.

Considerable evidence indicates that the syntheses of RNA and protein in nervous tissue can be significantly modified in relation to changes in the functional state of the tissue. An inhibitor of alkaline ribonuclease has been observed in the soluble fraction of number of mamm alian tissues. The ratio of inhibitor to alkalin e ribonuclease activity in high in those tissues characterized by high rates of RNAM synthesis and RNA accumulation. Conversely, those tissues in which protein synthesis decreases and catabolic activity activity increases demonstrate lower levels of the in hibitor and elevated alkaline ribonuclease activity. The possible importance of the ribonuclease in hibitor in RNA metabolism has prompted the author to study the kinetic characters between alkaline ribonuclease and its natural inhibitor in brain tissues. In the present work, the alkaline ribonuclease and its natural in hibitor were partially purified from albinorat brain tissues and kinetic properties and interaction between ribonuclease and natural inhibitor, as well as some other properties of them, also examined in this report. The results of the present experiment are summarized as followings ： 1. The alkaline ribonuclease was partially purified from the albinorat brain tissues, by the sequential treatments of acid and heat followed by salting out, dialysis, and DEAEcellulose colume chromatography w ith 46 fold of purification. But by omission of acid and heat treatment, the degree of purification was reduced. 2. The values of K m and Vmax of the present partially purified alkaline ribonuclese were 0 .130mg/ml and 182mU/ml, respectively. 3. The natural inhibitor was partially purified from the albinorat brain tissues by the consecutive treatment of salting out, dialysis and DEAE-cellulose column chromatography. In the DEAE-cellulose coumn chromatogram, two frections with inhibitory effect were observed. 4. The Ki value of this natural inhibitor again st the rat brain alkaline ribonuclease was 0 .24mg/ml. 5. The natural inhibitor showed noncompetitive in hibitor against alkaline ribonuclease. 6. The natural inhibitor partially purified in the present experiment showed heat lability and p-hydroxymeroxymercuribenzoate sensitivity.