title: Co-dependency of calcium and porphyrin for an integrated molecular structure of peanut peroxidase: a circular dichroism analysis.
abstract: The contribution of calcium to the structure of cationic peanut peroxidase was examined using ultraviolet/visible and circular dichroism spectroscopies under conditions in which the 2 moles of Ca2+ bound per mole of enzyme were removed. Cadmium and terbium ions were used as substitutes for calcium in the calcium depleted peroxidase and their influence on the protein structure was examined spectroscopically and compared to native and heme depleted enzymes. A role for the calcium ions in maintaining the active conformation of the peroxidase is proposed.
authors.affiliation: Department of Plant Sciences, University of Western Ontario, London, Canada.
authors.forename: M J
authors.initials: MJ
authors.lastname: Rodríguez Marañón
authors.forename: M J
authors.initials: MJ
authors.lastname: Stillman
authors.forename: R B
authors.initials: RB
authors.lastname: van Huystee
mesh_terms: D010367:Arachis / Q000201:enzymology; D002118:Calcium / Q000494:pharmacology*; D002412:Cations; D002942:Circular Dichroism; D004492:Edetic Acid / Q000494:pharmacology; D010544:Peroxidases / Q000737:chemistry* / Q000378:metabolism*; D011166:Porphyrins / Q000494:pharmacology*; D011487:Protein Conformation; D013053:Spectrophotometry; D013054:Spectrophotometry, Atomic
chemical_list: D002412:Cations; D011166:Porphyrins; D004492:Edetic Acid; D010544:Peroxidases; D002118:Calcium