title: Impact of Solvent pH on Direct Immobilization of Lysosome-Related Cell Organelle Extracts on TiO₂ for Melanin Treatment.
abstract: Techniques for immobilizing effective enzymes on nanoparticles for stabilization of the activity of free enzymes have been developing as a pharmaceutical field. In this study, we examined the effect of three different pH conditions of phosphate buffer, as a dissolving solvent for lysosomal enzymes, on the direct immobilization of lysosomal enzymes extracted from Hen's egg white and Saccharomyces cerevisiae. Titanium(IV) oxide (TiO2) nanoparticles, which are extensively used in many research fields, were used in this study. The lysosomal enzymes immobilized on TiO2 under each pH condition were evaluated to maintain the specific activity of lysosomal enzymes, so that we can determine the degree of melanin treatment in lysosomal enzymes immobilized on TiO2. We found that the immobilization efficiency and melanin treatment activity in both lysosomal enzymes extracted from Hen's egg white and S. cerevisiae were the highest in an acidic condition of phosphate buffer (pH 4). However, the immobilization efficiency and melanin treatment activity were inversely proportional to the increase in pH under alkaline conditions. In addition, enhanced immobilization efficiency was shown in TiO2 pretreated with a divalent, positively charged ion, Ca(2+), and the melanin treatment activity of immobilized lysosomal enzymes on TiO2 pretreated with Ca(2+) was also increased. Therefore, this result suggests that the immobilization efficiency and melanin treatment activity of lysosomal enzymes can be enhanced according to the pH conditions of the dissolving solvent.
authors.affiliation: Department of Bioprocess Engineering, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Seung Hyuck
authors.initials: SH
authors.lastname: Bang
authors.affiliation: Division of Chemical Engineering, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Pil
authors.initials: P
authors.lastname: Kim
authors.affiliation: Ecobio Inc, 804 New Business Care Center of Chonnam National University, Gwangju 500-757, Republic of Korea.
authors.forename: Suk-Jung
authors.initials: SJ
authors.lastname: Oh
authors.affiliation: Deparment of Microbiology, Chungbuk National University, Cheongju 361-763, Republic of Korea.
authors.forename: Yang-Hoon
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Bioprocess Engineering, Chonbuk National University, Jeonju 561-756, Republic of Korea.|Division of Chemical Engineering, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Jiho
authors.initials: J
authors.lastname: Min
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002645:Chickens; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008247:Lysosomes / Q000737:chemistry* / Q000378:metabolism; D008543:Melanins / Q000737:chemistry / Q000378:metabolism*; D012997:Solvents; D014025:Titanium / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D008543:Melanins; D012997:Solvents; C009495:titanium dioxide; D014025:Titanium; D002118:Calcium