Record Details
The purification and characterization of a ribonuclease from bovine aorta
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | The purification and characterization of a ribonuclease from bovine aorta |
| Names |
Lewis, Roger Allen
(creator) Gamble, Wilbert (advisor) |
| Date Issued | 1968-03-28 (iso8601) |
| Note | Graduation date: 1968 |
| Abstract | Reports of investigations on nucleases in arterial tissue are few in number. The present study is concerned with the purification and characterization of an aortic ribonuclease. An endonuclease (ARNase I) isolated from the bovine aorta has been purified 4611 fold by means of fractionation with ethanol, acid extraction, isoionic precipitation, BioRex 70 column chromatography and dialysis. A second fraction from BioRex 70 column chromatography, ARNase II, was partially purified 667 fold. A pH optimum for ARNase I activity on 0.5% sodium RNA was observed at 7.5 and no activity was detected at pH 5.1. The enzyme exhibited a temperature optimum of 60°C. Polyuridylic acid (poly U) was rapidly depolymerized by ARNase I, whereas polycytidylic acid (poly C) was only slowly hydrolyzed by the enzyme at a rate of 1/24 that exhibited on poly U. Polyguanylic acid, polyadenylic acid and polyinosinic acid were resistant to enzymatic action. ARNase II was 18 times more active on poly C and one-seventh as active on poly U as was ARNase I. Cytidylyl-(3'-5')-cytidine and uridylyl-(3'-5')-cytidine were hydrolized by ARNase I with the products being 2', 3'-cyclic cytidylic acid and cytidine and 2', 3'-cyclic uridylic acid and cytidine, respectively. Adenylyl-(3'-5')-cytidine and guanylyl-(3'-5')-cytidine were not acted upon by the enzyme. On incubation of sodium RNA with ARNase I, only 16% of the acid soluble nucleotides were present as oligonucleotides of three units or less. These data show that ARNase I is an endonuclease with a specificity for the formation of pyrimidine phosphates during the hydrolysis of polynucleotides and a preference for uridylic acid residues. |
| Genre | Thesis/Dissertation |
| Topic | Ribonucleases |
| Identifier | http://hdl.handle.net/1957/46726 |
