title: Study of the electrostatic effects of mutations on the surface of dehaloperoxidase-hemoglobin A.
abstract: Point mutations of dehaloperoxidase-hemoglobin A (DHP A) that affect the surface charge have been prepared to study the interaction between DHP A with its substrate 2,4,6-trichlorophenol (TCP). Kinetic studies of these surface mutations showed a correlation, in which the more positively charged mutants have increased catalytic efficiency compared with wild type DHP A. As a result, the hypothesis of this study is that there is a global electrostatic interaction between DHP A and TCP. The electrostatic nature of substrate binding was further confirmed by the result that kinetic assays of DHP A were affected by ionic strength. Furthermore, isoelectric focusing (IEF) gel study showed that the pI-6.8 for DHP A, which indicates that DHP A has a slight negative charge pH 7, consistent with the kinetic observations.
authors.affiliation: Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Junjie
authors.initials: J
authors.lastname: Zhao
authors.forename: Jennifer
authors.initials: J
authors.lastname: Rowe
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Franzen
authors.forename: Chi
authors.initials: C
authors.lastname: He
authors.forename: Stefan
authors.initials: S
authors.lastname: Franzen
mesh_terms: D000818:Animals; D006441:Hemoglobin A / Q000737:chemistry* / Q000235:genetics; D016296:Mutagenesis; D009154:Mutation; D010544:Peroxidases / Q000737:chemistry* / Q000235:genetics; D011077:Polychaeta / Q000201:enzymology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D055672:Static Electricity
chemical_list: D011994:Recombinant Proteins; D006441:Hemoglobin A; D010544:Peroxidases