J. Biochem, 1988, Vol. 103, No. 2 267-273
© 1988 Japanese Biochemical Society
research-article |
Purification of Acid Ribonucleases from Bovine Spleen
* Department of Microbiology, Hoshi College of Pharmacy Shinagawa-ku, Tokyo 142
** Azabu University Sagamihara, Kanagawa 229
1To whom correspondence should addressed.
Two acid RNases were purified from bovine spleen by means of ammonium sulfate fractionation, chromatographies on. phospho-cellulose, heparin-Sepharose CL-6B, poly G-Sepharose, and 2', 5'-ADP-Sepharose, and gel filtration on Toyopearl HW 55F. Both purified preparations were homogeneous as judged by disc electrophoresis at pH 4.3. They were designated as RNase BSP1 and RNase BSP2 in the order of elution from a phospho-cellulose column. RNase BSP2 was immunologically indistinguishable from RNase K2 from bovine kidney. RNase BSP1 was a typical pyrimidine base-specific, uridylic acid-preferential RNase and had very sharp pH optimum at 6.5. RNase BSP1 thus obtained was a glycoprotein giving two major bands on SDS-slab electrophoresis. Although the apparent molecular weight of RNase BSP, was distributed in the range of 27,000-20,000, it decreased to about 17,000-18,000 after endoglycosidase F digestion. The N-terminal amino acid sequence up to the 20th amino acid had no homology to those of RNase K2 and RNase A.