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A histidine residue in p-hydroxybenzoate hydroxylase essential for binding of reduced nicotinamide adenine dinucleotide phosphate
- Source :
- Journal of Biological Chemistry. 257:3422-3428
- Publication Year :
- 1982
- Publisher :
- Elsevier BV, 1982.
-
Abstract
- Chemical modification with diethylpyrocarbonate (ethoxyformic anhydride) was examined to demonstrate the existence of an essential histidine residue at the NADPH-binding site of p-hydroxybenzoate hydroxylase (EC 1.14.13.2) from Pseudomonas desmolytica. Among some ligands, NADPH was noticeable in protecting the enzyme from the modification-caused inactivation. Although several amino acid residues were modified during the inactivation process, inhibition of the enzyme could be correlated with modification of a single histidine residue which was masked by addition of NADPH. The pK of the essential histidine residue was estimated to be 6.5-6.7. The Kd (Km) for NADPH of the inactivated enzyme was shown to have been increased greatly, although the Kd for substrate (p-hydroxybenzoate) was not changed.
- Subjects :
- Formates
Stereochemistry
Kinetics
Hydroxylamines
Biochemistry
Mixed Function Oxygenases
chemistry.chemical_compound
Pseudomonas
Diethyl Pyrocarbonate
Histidine
Molecular Biology
chemistry.chemical_classification
Histidine residue
Substrate (chemistry)
Chemical modification
Cell Biology
4-Hydroxybenzoate-3-Monooxygenase
Phosphate
Histidine decarboxylase
Dithiothreitol
Enzyme
chemistry
NADP
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 257
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....0056b9329951ede25ead094ad00779c7