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 trimers, tetramers, pentamers and hexamers) were obtained by lyophilization of RNase A from 40-50% acetic acid solutions. The RNase activity of these aggregates was compared with that of monomeric RNase A on single- and double-stranded polyribonucleotides. Their activity toward poly(U) and yeast RNA slightly decreases as a function of the size of the aggregates. In contrast, their action on poly(A).poly(U) as substrate progressively increases from a relative activity of 1 for the RNase monomer to 10 for the hexamer. These results are discussed in the light of an already advanced hypothesis about a possible mechanism of RNase attack on double-stranded RNA.
Libonati
M
M
Istituto di Chimica Biologica, Facoltà di Medicine e Chirurgla, Università di Verona, Italy.
Bertoldi
M
M
Sorrentino
S
S
D000818:Animals; D001704:Biopolymers / Q000378:metabolism; D002417:Cattle; D002850:Chromatography, Gel; D004795:Enzyme Stability; D009690:Nucleic Acid Conformation; D010179:Pancreas / Q000201:enzymology; D011063:Poly A-U / Q000378:metabolism; D011072:Poly U / Q000378:metabolism; D011487:Protein Conformation; D012330:RNA, Double-Stranded / Q000378:metabolism*; D012259:Ribonuclease, Pancreatic / Q000737:chemistry / Q000378:metabolism*; D015003:Yeasts
D001704:Biopolymers; D012330:RNA, Double-Stranded; D011063:Poly A-U; D011072:Poly U; D012259:Ribonuclease, Pancreatic