ISSN:
1432-2048
Keywords:
Cell culture (RNase)
;
Lycopersicon vacuolar RNase
;
Ribonuclease
;
Vacuole (enzyme localization)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract A ribonuclease which was previously shown to be located in isolated vacuoles from suspension-cultured cells of tomato (Lycopersicon esculentum L.; Abel and Glund 1986, Physiol. Plant. 66, 79–86) has been purified to near homogeneity. Purification was up to 55000-fold with a yield of about 20%. The vacuolar origin of the protein was evidenced by comparing its electrophoretic mobility, isoelectric point, pH-optimum for activity and other properties with that of the RNA-degrading activity present in isolated vacuoles. The molecular weight of the native single polypeptide chain was estimated at 17500 and 20300 by gel filtration and sedimentation analysis, respectively. The enzyme hydrolyzed only single-stranded RNA with a mode of action that was endonucleolytic. The vacuolar ribonuclease had no requirement for divalent metal ions, and did not exhibit phosphomonoesterase (EC 3.1.3.1; EC 3.1.3.2) and phosphodiesterase (EC 3.1.15.1; EC 3.1.16.1) activity. The specificity of the enzyme has been studied by using homopolyribonucleotides as substrates. The end-products obtained were the respective nucleoside 2′:3′-cyclic monophosphates and, to minor extents, the corresponding nucleoside 3′(2′)-monophosphates. According to these observations, the vacuolar ribonuclease from tomato can be classified as ribonuclease I (EC 3.1.27.1).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00403030
Permalink
