title: Purification of a polyphenol oxidase isoform from potato (Solanum tuberosum) tubers.
abstract: A different expression pattern of polyphenol oxidases has been observed during storage in cultivars of potato (Solanum tuberosum L.) featuring different length of dormancy: a short-dormant cultivar showed, at the end of the dormancy, both the highest polyphenol oxidase activity and the largest number of enzyme isoforms. An isoform of polyphenol oxidase isolated at the end of the physiological dormancy from a short-dormant cultivar has been purified to homogeneity by means of column chromatography on phenyl Sepharose and on Superdex 200. The purification factor has been determined equal to 88, and the molecular mass of the purified isoform has been estimated to be 69 and 340 kDa by SDS polyacrylamide gel electrophoresis and gel filtration on Superdex 200, respectively, indicating this PPO isoform as a multimer. The corresponding zymogram features a diffused single band at the cathodic region of the gel and the pI of this polyphenol oxidase has been calculated equal to 6.5.
authors.affiliation: Department of Industrial Chemistry, University of Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy.
authors.forename: Costanza
authors.initials: C
authors.lastname: Marri
authors.forename: Alessandra
authors.initials: A
authors.lastname: Frazzoli
authors.forename: Alejandro
authors.initials: A
authors.lastname: Hochkoeppler
authors.forename: Valeria
authors.initials: V
authors.lastname: Poggi
mesh_terms: D004156:Catechol Oxidase / Q000302:isolation & purification*; D007526:Isoelectric Point; D035281:Plant Tubers / Q000737:chemistry*; D020033:Protein Isoforms / Q000302:isolation & purification*; D011198:Solanum tuberosum / Q000737:chemistry*
chemical_list: D020033:Protein Isoforms; D004156:Catechol Oxidase