Steady-state kinetic studies of the inhibitory action of Zn2+ on ribonuclease T1 catalysis.

Mitsuhiro Itaya, Y. Inoue

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The kinetic mechanism of specific inhibition by Zn2+ of ribonuclease T1 catalysis was studied by steady-state kinetic analysis of transphosphorylation of dinucleotides, GpCp(3'), GpUp(2') and GpUp(3'), and dinucleoside monophosphates, GpC and GpU. The inhibition was not simply competitive, non-competitive or uncompetitive, but the kinetic data were compatible with a mechanism of 'fully mixed inhibition' in which a fully non-competitive action was associated with a partially competitive action. Apparent equilibrium quotients involved in this model of inhibition were determined for the dinucleotide substrates, and we found that binding of either of Zn2+ and substrate was facilitated when the other was bound. The location of Zn2+ was suggested to be near His-40 and/or His-92 of the ribonuclease T1 molecule.

Original languageEnglish
Pages (from-to)357-362
Number of pages6
JournalBiochemical Journal
Volume207
Issue number2
Publication statusPublished - 1982 Nov 1
Externally publishedYes

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Ribonuclease T1
Catalysis
Kinetics
Dinucleoside Phosphates
Substrates
Molecules
guanylyl(3'-5')uridine 3'-monophosphate

ASJC Scopus subject areas

  • Biochemistry

Cite this

Steady-state kinetic studies of the inhibitory action of Zn2+ on ribonuclease T1 catalysis. / Itaya, Mitsuhiro; Inoue, Y.

In: Biochemical Journal, Vol. 207, No. 2, 01.11.1982, p. 357-362.

Research output: Contribution to journalArticle

Itaya, Mitsuhiro ; Inoue, Y. / Steady-state kinetic studies of the inhibitory action of Zn2+ on ribonuclease T1 catalysis. In: Biochemical Journal. 1982 ; Vol. 207, No. 2. pp. 357-362.
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