THE ACTIVITY ON DOUBLE-STRANDED-RNA OF AGGREGATES OF RIBONUCLEASE-A HIGHER THAN DIMERS INCREASES AS A FUNCTION OF THE SIZE OF THE AGGREGATES

Stable bovine RNase A aggregates larger than dimers (identified as tri mers, tetramers, pentamers and hexamers) were obtained by lyophilizati on of RNase A from 40-50 % acetic acid solutions. The RNase activity o f these aggregates was compared with that of monomeric RNase A on sing le- and double-stranded poly ribonucleotides. Their activity toward po ly(U) and yeast RNA slightly decreases as a function of the size of th e aggregates, In contrast, their action on poly(A),poly(U) as substrat e progressively increases from a relative activity of 1 for the RNase monomer to 10 for the hexamer, These results are discussed in the ligh t of an already advanced hypothesis about a possible mechanism of RNas e attack on double-stranded RNA.