Inactivation of E. coli RNA polymerase by pyridoxal 5′-phosphate: Identification of a low pKa lysine as the modified residue

Paulina Bull, Josefina Zaldivar, Alejandro Venegas, Joseph Martial, Pablo Valenzuela

Resultado de la investigación: Article

25 Citas (Scopus)

Resumen

The inactivation of E. coli RNA polymerase (3.3 × 10-7M) by pyridoxal 5′-phosphate (1 × 10-4M to 5 × 10-4M) is a first order process with respect to the remaining active enzyme. Studies of the variation of the first order rate constant with the concentration of pyridoxal 5′-phosphate show that the inactivation reaction follows saturation kinetics. The formation of a reversible enzyme-inhibitor intermediate is postulated. Kinetic studies at different pH values indicate that the inactivation rate constant depends on the mole fraction of one conjugate base with pKa 7.9. The apparent equilibrium constant (association) for the inactivation reaction is independent of the pH and is 1.8 × 104 M-1. By electrophoretic and chromatographic analysis of enzyme hydrolyzates after pyridoxal 5′-phosphate and NaBH4 treatment only N-ε{lunate}-pyridoxyllysine was found. It is postulated that a lysine ε{lunate}-amino group with a low pKa is critical for the activity of the enzyme.

Idioma originalEnglish
Páginas (desde-hasta)1152-1159
Número de páginas8
PublicaciónBiochemical and Biophysical Research Communications
Volumen64
N.º4
DOI
EstadoPublished - 16 jun 1975

Huella dactilar

Pyridoxal Phosphate
DNA-Directed RNA Polymerases
Escherichia coli
Lysine
Rate constants
Enzymes
Chromatographic analysis
Kinetics
Equilibrium constants
Enzyme Inhibitors
Chromatography
Association reactions

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

Citar esto

Bull, Paulina ; Zaldivar, Josefina ; Venegas, Alejandro ; Martial, Joseph ; Valenzuela, Pablo. / Inactivation of E. coli RNA polymerase by pyridoxal 5′-phosphate : Identification of a low pKa lysine as the modified residue. En: Biochemical and Biophysical Research Communications. 1975 ; Vol. 64, N.º 4. pp. 1152-1159.
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abstract = "The inactivation of E. coli RNA polymerase (3.3 × 10-7M) by pyridoxal 5′-phosphate (1 × 10-4M to 5 × 10-4M) is a first order process with respect to the remaining active enzyme. Studies of the variation of the first order rate constant with the concentration of pyridoxal 5′-phosphate show that the inactivation reaction follows saturation kinetics. The formation of a reversible enzyme-inhibitor intermediate is postulated. Kinetic studies at different pH values indicate that the inactivation rate constant depends on the mole fraction of one conjugate base with pKa 7.9. The apparent equilibrium constant (association) for the inactivation reaction is independent of the pH and is 1.8 × 104 M-1. By electrophoretic and chromatographic analysis of enzyme hydrolyzates after pyridoxal 5′-phosphate and NaBH4 treatment only N-ε{lunate}-pyridoxyllysine was found. It is postulated that a lysine ε{lunate}-amino group with a low pKa is critical for the activity of the enzyme.",
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Inactivation of E. coli RNA polymerase by pyridoxal 5′-phosphate : Identification of a low pKa lysine as the modified residue. / Bull, Paulina; Zaldivar, Josefina; Venegas, Alejandro; Martial, Joseph; Valenzuela, Pablo.

En: Biochemical and Biophysical Research Communications, Vol. 64, N.º 4, 16.06.1975, p. 1152-1159.

Resultado de la investigación: Article

TY - JOUR

T1 - Inactivation of E. coli RNA polymerase by pyridoxal 5′-phosphate

T2 - Identification of a low pKa lysine as the modified residue

AU - Bull, Paulina

AU - Zaldivar, Josefina

AU - Venegas, Alejandro

AU - Martial, Joseph

AU - Valenzuela, Pablo

PY - 1975/6/16

Y1 - 1975/6/16

N2 - The inactivation of E. coli RNA polymerase (3.3 × 10-7M) by pyridoxal 5′-phosphate (1 × 10-4M to 5 × 10-4M) is a first order process with respect to the remaining active enzyme. Studies of the variation of the first order rate constant with the concentration of pyridoxal 5′-phosphate show that the inactivation reaction follows saturation kinetics. The formation of a reversible enzyme-inhibitor intermediate is postulated. Kinetic studies at different pH values indicate that the inactivation rate constant depends on the mole fraction of one conjugate base with pKa 7.9. The apparent equilibrium constant (association) for the inactivation reaction is independent of the pH and is 1.8 × 104 M-1. By electrophoretic and chromatographic analysis of enzyme hydrolyzates after pyridoxal 5′-phosphate and NaBH4 treatment only N-ε{lunate}-pyridoxyllysine was found. It is postulated that a lysine ε{lunate}-amino group with a low pKa is critical for the activity of the enzyme.

AB - The inactivation of E. coli RNA polymerase (3.3 × 10-7M) by pyridoxal 5′-phosphate (1 × 10-4M to 5 × 10-4M) is a first order process with respect to the remaining active enzyme. Studies of the variation of the first order rate constant with the concentration of pyridoxal 5′-phosphate show that the inactivation reaction follows saturation kinetics. The formation of a reversible enzyme-inhibitor intermediate is postulated. Kinetic studies at different pH values indicate that the inactivation rate constant depends on the mole fraction of one conjugate base with pKa 7.9. The apparent equilibrium constant (association) for the inactivation reaction is independent of the pH and is 1.8 × 104 M-1. By electrophoretic and chromatographic analysis of enzyme hydrolyzates after pyridoxal 5′-phosphate and NaBH4 treatment only N-ε{lunate}-pyridoxyllysine was found. It is postulated that a lysine ε{lunate}-amino group with a low pKa is critical for the activity of the enzyme.

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