Resolution of the flavocytochrome p-cresol methylhydroxylase into subunits and reconstitution of the enzyme
- 1 September 1985
- journal article
- research article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 24 (19), 5276-5280
- https://doi.org/10.1021/bi00340a048
Abstract
An improved procedure is described for the isolation of the flavocytochrome p-cresol methylhydroxylase (PCMH) from Pseudomonas putida as well as methods for the separation of its subunits in native form and their recombination to reconstitute the original flavocytochrome. Under appropriate conditions, the reconstitution is stoichiometric and results in complete recovery of the catalytic activity of the flavocytochrome. The separated flavoprotein subunit shows only 2% of the catalytic activity of the original enzyme on p-cresol and is characterized by converging lines in bisubstrate kinetic analysis, while the intact and reconstituted enzymes show parallel line kinetics in steady-state experiments. van''t Hoff plots of the dependence of the dissociation constant of the subunits of PCMH on temperature show a break near 15.degree. C. Above this temperature, KD is characterized by a positive .DELTA.H value of 12.6 kcal mol-1; below 15.degree. C, the dissociation is essentially temperature independent. The subunit dissociation is strongly dependent on ionic strength in the oxidized form of PCMH but not in the reduced form of the enzyme. Reduction also lowers the KD significantly, while substrates and nonoxidizable competitive inhibitors lower the dissociation constant even further, suggesting a conformation change. Combination of the subunits to form PCMH entails a small but measurable change in the absorption spectra of the component proteins.This publication has 11 references indexed in Scilit:
- p-Cresol methylhydroxylase. Assay and general propertiesBiochemical Journal, 1985
- Laser-flash-photolysis studies of p-cresol methylhydroxylase. Electron-transfer properties of the flavin and haem componentsBiochemical Journal, 1985
- Stereochemistry of 1-(4′-hydroxyphenyl)ethanol produced by hydroxylation of 4-ethylphenol by p-cresol methylhydroxylaseBiochemical Journal, 1984
- 8.alpha.-(O-Tyrosyl)flavin adenine dinucleotide, the prosthetic group of bacterial p-cresol methylhydroxylaseBiochemistry, 1981
- P-cresol and 3,5-xylenol methylhydroxylases in Pseudomonas putida N.C.I.B. 9896Biochemical Journal, 1978
- Incorporation of [18O]water in the formation of p-hydroxybenzyl alcohol by the p-cresol methylhydroxylase from Pseudomonas putidaBiochemical Journal, 1978
- Electrophoretic concentration of macromoleculesAnalytical Biochemistry, 1978
- The purification and properties of p-cresol-(acceptor) oxidoreductase (hydroxylating), a flavocytochrome from Pseudomonas putidaBiochemical Journal, 1977
- Nonisoelectric focusing in buffersAnalytical Biochemistry, 1976
- The hydroxylation of p-cresol and its conversion to p-hydroxybenzaldehyde in Pseudomonas putidaBiochemical and Biophysical Research Communications, 1976