title: Purification of cytochrome b-561 from bean hypocotyls plasma membrane. Evidence for the presence of two heme centers.
abstract: The high potential, ascorbate-reducible b-type cytochrome of plant plasma membranes, named cytochrome b-561, has been purified to homogeneity from etiolated bean hypocotyls. The pure protein migrated in denaturing electrophoresis as a broad band of approximately 55 kDa, and was found to be glycosylated. Optical redox titrations of partially purified cytochrome b-561 indicated that it contains two hemes with similar spectral features, but distinct midpoint redox potentials (E(m7)+135 mV and +206 mV, respectively). The presence of two heme centers in cytochrome b-561 is consistent with its role in electron transfer across plant plasma membranes.
authors.affiliation: Department of Biology, University of Bologna, Via Irnerio 42, I-40126 Bologna, Italy. trost@alma.unibo.it
authors.forename: P
authors.initials: P
authors.lastname: Trost
authors.forename: A
authors.initials: A
authors.lastname: Bèrczi
authors.forename: F
authors.initials: F
authors.lastname: Sparla
authors.forename: G
authors.initials: G
authors.lastname: Sponza
authors.forename: B
authors.initials: B
authors.lastname: Marzadori
authors.forename: H
authors.initials: H
authors.lastname: Asard
authors.forename: P
authors.initials: P
authors.lastname: Pupillo
mesh_terms: D002462:Cell Membrane / Q000737:chemistry; D002852:Chromatography, Ion Exchange; D003573:Cytochrome b Group / Q000737:chemistry / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D007887:Fabaceae / Q000737:chemistry*; D006418:Heme / Q000737:chemistry; D018546:Hypocotyl / Q000737:chemistry; D010946:Plants, Medicinal; D011199:Potentiometry; D013053:Spectrophotometry
chemical_list: D003573:Cytochrome b Group; C023646:cytochrome b561; D006418:Heme