Human pancreatic-type ribonucleases with activity against double-stranded ribonucleic acids.
Purified acid-thermostable ribonuclease (Ribonucleate 3'-pyrimidino-oligonucleotidohydrolase, EC 3.1.4.22) from human pancreas degrades double-stranded RNA at 2% the rate for single-stranded RNA. The activities against single-stranded RNA and double-stranded RNA were shown to be due to a single enzyme with properties similar to bovine pancreatic RNAase A. For purposes of comparison the activities against double-stranded RNA of crystalline ribonucleases of the whale, rat and cow were assayed and found to be 0.4%, 0.03% and 0.003%, respectively, of their activities against single-stranded RNA. Both human serum and urine contain RNAse components of pancreatic origin which hydrolyze double-stranded RNA at 2% and 0.4%, respectively, of the rates against single-stranded RNA. By contrast, purified acid-thermostable RNAases from human spleen and liver hydrlyze double-stranded RNA at least 20-fold more slowly than human pancreatic RNAase, relative to the corresponding rates against single-stranded RNA. The human pancreatic and serum enzymes exhibit appreciable activity against the poly(C) component of the double-stranded poly(I)-poly(C); they also attack poly(C) itself at approximately 25 times the rate for poly(U) and at more than 50 times the rate for single-stranded RNA.
D000818:Animals; D004355:Drug Stability; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009928:Organ Specificity; D010179:Pancreas / Q000201:enzymology*; D011070:Poly I-C; D012260:Ribonucleases / Q000378:metabolism*; D013045:Species Specificity; D013329:Structure-Activity Relationship; D013696:Temperature
D012260:Ribonucleases; D011070:Poly I-C