RNA polymerase I from higher plants. Evidence for allosteric regulation and interaction with a nuclear phosphatase activity controlled NTP pool

RNA polymerase I was isolated from parsley cells grown In suspension culture and from soybean hypocotyls. Kinetic studies of the enzyme revealed that RNA polymerase I is an allosteric regulated enzyme. The enzyme activity was influenced by nucleoside triphosphates (NTP) and divalent cations. NTP exc...

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Bibliographic Details
Published in:Nucleic acids research 1979-12, Vol.7 (7), p.2015-2029
Main Authors: Grossmann, K, Seitz, U
Format: Article
Language:English
Subjects:
Allosteric Regulation
Cations, Divalent
Cell Nucleus - metabolism
DNA-Directed RNA Polymerases - metabolism
Glycine max
Kinetics
Nucleoside-Triphosphatase
Nucleotides - metabolism
Phosphoric Monoester Hydrolases - metabolism
plant biochemistry
plant physiology
Plants - metabolism
RNA Polymerase I - metabolism
Vegetables
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Summary:RNA polymerase I was isolated from parsley cells grown In suspension culture and from soybean hypocotyls. Kinetic studies of the enzyme revealed that RNA polymerase I is an allosteric regulated enzyme. The enzyme activity was influenced by nucleoside triphosphates (NTP) and divalent cations. NTP exceeding a 1:1 ratio of these two components acted as allosteric inhibitors, contrary to free divalent cations, which had promotive effects on the RNA polymerase I. Furthermore, isolated nuclei from parsley exhibited a powerful nucleoside triphos-phatase (NTPase) activity. Contrary to RNA polymerase I, this enzyme was stimulated by NTP exceeding the 1:1 ratio of NTP and divalent cations. Free divalent cations had an inhibitory effect. Assuming that a causal connection of these two processes does exist, a possible role of this NTPase would be the control of NTP pools in relation to divalent cations and thus regulating RNA synthesis.
ISSN:0305-1048
1362-4962
DOI:10.1093/nar/7.7.2015