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The Presence of a Ribonuclease of High Molecular Weight in Sugar Beet Storage Tissue
Author(s) -
GUERRIERO VINCENT,
DUNHAM VALGENE L.
Publication year - 1979
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1979.tb06504.x
Subject(s) - ribonuclease , ammonium sulfate precipitation , sugar beet , sephadex , chemistry , enzyme assay , chromatography , biochemistry , enzyme , substrate (aquarium) , ammonium sulfate , specific activity , size exclusion chromatography , rna , biology , horticulture , ecology , gene
Soluble ribonuckasie activity in sliced root tissue or sugar beet ( Beta vulgaris ) decreased to 30% of initial levels during the first 15 hours of aeration in sterile phosphate buffer. Activity increased with continued aeration reaching a maximum at 30 hours (85% of initial levels). Ribonuclease activity was isolated from unaerated tissue and partially purified by precipitation with acid and ammonium sulfate and by Sephadex chromatography. Enzyme activity was linear with respect to enzyme and substrate concentrations. The enzyme exhibited a substrate preference for RNA with no activity in the presence of native or denatured DNA. Elution of the enzyme from a Sephadex G‐150 column indicated a molecular weight of 155,000. This uniquely large ribonuclease had no phosphodiesterase activity, was unaffected by ethylenediamine tetraacetate, and was inhibited by increasing Nig 2+ concentrations.