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The reactive lysine residue at the allosteric site of sheep kidney pyruvate carboxylase
- Source :
- Biochimica et biophysica acta. 151(2)
- Publication Year :
- 1968
-
Abstract
- Investigations have revealed that sheep kidney pyruvate carboxylase (pyruvate: CO2 ligase (ADP), EC 6.4.1.1) possesses a lysine residue whose integrity is essential for enzymic activity. Modification of the enzyme with amino group reagents such as 1-fluoro-2,4-dinitrobenzene, trinitrobenzene sulphonic acid and potassium cyanate resulted in a loss of catalytic activity. The characterisation of the major radioactive dinitrophenyl-amino acid derivative of 1-fluoro-2,4-dinitro[14C]benzene labelled enzyme as e-dinitrophenyl-lysine confirmed the identity of the reactive residue. Inhibition of the enzyme by 1-fluoro-2,4-dinitrobenzene and trinitrobenzene sulphonic acid was first order with respect to time and inhibitor concentration. From the kinetic data obtained, it was concluded that an average of 1 molecule of these reagents reacts with the enzyme causing inactivation. The rate of inactivation with these reagents was pH dependent, increasing with increasing pH values. The ability of the allosteric effector, acetyl-CoA, to protect the enzyme against inhibition by these reagents suggested that the e-amino group of lysine may be involved in the enzyme-acetyl-CoA interaction. The dissociation constant for the enzyme-acetyl-CoA complex was 5.4·10−4 M.
- Subjects :
- Electrophoresis
Paper
Protein Denaturation
Allosteric regulation
Lysine
Kidney
Ligases
Residue (chemistry)
chemistry.chemical_compound
Animals
Coenzyme A
chemistry.chemical_classification
DNA ligase
Carbon Isotopes
Binding Sites
Sheep
General Medicine
Hydrogen-Ion Concentration
Pyruvate carboxylase
Dissociation constant
Kinetics
Enzyme
Freeze Drying
Biochemistry
chemistry
Potassium cyanate
Subjects
Details
- ISSN :
- 00063002
- Volume :
- 151
- Issue :
- 2
- Database :
- OpenAIRE
- Journal :
- Biochimica et biophysica acta
- Accession number :
- edsair.doi.dedup.....b4d45cecd2164dcc97cb140c101065ab