Purification of a calcium dependent ribonuclease from Xenopus laevis.
We have purified a Ca2+ dependent ribonuclease from the oocytes of Xenopus leavis. Two properties of this ribonuclease set it apart from other known nucleases. First, Ca2+ was required for ribonuclease activity, and Mg2+ would not substitute. Second, the enzyme specifically degraded RNA and digestion of double or single stranded DNA was not observed. Ca2+ dependent ribonuclease activity of the purified 36-kDa protein was directly observed after renaturation of the protein following electrophoresis in an SDS-Laemmli gel. In addition, the enzyme was shown to have endoribonuclease activity at numerous sites. The Ca2+ dependence suggests that the ribonuclease activity may be modulated by changes in the level of intracellular Ca2+ and thereby provide a direct link to signal transduction systems.
Seidel
C W
CW
Sinsheimer Laboratories, University of California, Santa Cruz 95064.
Peck
L J
LJ
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D009865:Oocytes / Q000201:enzymology; D012260:Ribonucleases / Q000302:isolation & purification* / Q000378:metabolism; D015398:Signal Transduction; D014982:Xenopus laevis
D012260:Ribonucleases; D002118:Calcium