title: Immobilization of hemoglobin at the galleries of layered niobate HCa2Nb3O10.
abstract: Hemoglobin (Hb) was intercalated at the galleries of layered niobate HCa(2)Nb(3)O(10) (HCNO). Two different kinds of layered phases of Hb-CNO composites Hb-CNO-1 and Hb-CNO-2 were obtained with the interlayer distances of 7.2 and 10.3nm in correspondence with the monolayer and bilayer arrangements of proteins between the niobate layers, respectively, based on the powder XRD pattern, HRTEM, UV-vis spectra and CHN analyses. FTIR spectra of Hb-CNO composites show that amide I and amide II bands were actually the same as those of the native Hb, which indicates that there is almost no structural change after immobilization. Michaelis-Menten model methods were used to study the peroxidatic activity of the reaction of 2-methoxyphenol and H(2)O(2) for the entrapped Hb in the galleries of HCNO. Compared to that of free Hb, the kinetic parameters of Hb-CNO k(cat), K(M) and k(cat)/K(M) were affected by the immobilization process. The immobilized Hb showed a higher relative activity than that of free Hb after incubated in phosphate buffer (pH = 7) at 80 degrees C for a period of time. The environments between the layers of HCNO are hydrophilic which will bind water tightly and help to stabilize the 'essential water' layer around the protein. So, immobilization of Hb between the layers of HCNO enhanced the activity of Hb in water-DMSO mixture.
authors.affiliation: State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Graduate School, Chinese Academy of Sciences, People's Republic of China.
authors.forename: Lu
authors.initials: L
authors.lastname: Gao
authors.forename: Qiuming
authors.initials: Q
authors.lastname: Gao
authors.forename: Qigang
authors.initials: Q
authors.lastname: Wang
authors.forename: Shuge
authors.initials: S
authors.lastname: Peng
authors.forename: Jianlin
authors.initials: J
authors.lastname: Shi
mesh_terms: D000327:Adsorption; D001665:Binding Sites; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000032:analysis / Q000737:chemistry; D006454:Hemoglobins / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure; D007700:Kinetics; D008422:Materials Testing; D049329:Nanostructures / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure; D009556:Niobium / Q000032:analysis / Q000737:chemistry*; D011485:Protein Binding
chemical_list: D020099:Coated Materials, Biocompatible; D004800:Enzymes, Immobilized; D006454:Hemoglobins; D009556:Niobium