title: Redox potential of the haem c group in the quinocytochrome, lupanine hydroxylase, an enzyme located in the periplasm of a Pseudomonas sp.
abstract: The quinocytochrome c, lupanine hydroxylase, was shown to be located in the periplasm of a Pseudomonas sp. The midpoint redox potential of the haem in the purified enzyme was measured by potentiometric titration and shown to be +193 mV. PQQ was removed from the enzyme by isoelectric focusing to give inactive apoenzyme. This resulted in a shift in the midpoint redox potential of the haem to +98 mV. Full activity was recovered by the addition of PQQ to apoenzyme that also restored the original potential.
authors.affiliation: Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Hopper
authors.forename: J
authors.initials: J
authors.lastname: Rogozinski
mesh_terms: D002458:Cell Fractionation; D006418:Heme / Q000031:analogs & derivatives* / Q000737:chemistry; D016015:Logistic Models; D015394:Molecular Structure; D010084:Oxidation-Reduction; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000032:analysis*; D019897:Periplasm / Q000201:enzymology*; D011199:Potentiometry; D011549:Pseudomonas / Q000201:enzymology* / Q000648:ultrastructure; D017186:Titrimetry
chemical_list: C031690:heme C; D006418:Heme; C023929:lupanine hydroxylase; D000587:Oxidoreductases Acting on CH-NH Group Donors