Substrate and product inhibition initial rate kinetics of histone acetyltransferase

John E. Wiktorowicz, Kenneth L. Campos, James Bonner

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Abstract

Initial velocity and product inhibition kinetics of the histone acetyltransferase (EC 2.3.1.48) reaction indicate that the rat liver nuclear enzyme operates under a rapid equilibrium ordered bireactant mechanism. Histone adds first to the enzyme, and under the conditions of the experiment Ka = 0 as acetyl coenzyme A (CoA) concentration approaches saturating conditions. The Km for acetyl-CoA was 2.10 ± 0.48 μM. Inhibition with acetyllysine resulted in a Kiq for the enzyme-acetyllysine complex of 1.96 ± 0.30 mM. Inhibition with CoA yielded Kip for the ternary complex of 3.19 ± 0.48 μM. These results indicate that the enzyme activity is comparatively independent of histone concentration, and, since the enzyme is sensitive only to acetyl-CoA and CoA concentrations, the enzyme will tend to maintain histones in the acetylated state.

Original languageEnglish (US)
Pages (from-to)1464-1467
Number of pages4
JournalBiochemistry
Volume20
Issue number6
StatePublished - 1981
Externally publishedYes

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ASJC Scopus subject areas

  • Biochemistry

Cite this

Wiktorowicz, J. E., Campos, K. L., & Bonner, J. (1981). Substrate and product inhibition initial rate kinetics of histone acetyltransferase. Biochemistry, 20(6), 1464-1467.