Covalent attachment of cholesterol oxidase and horseradish peroxidase on perlite through silanization: activity, stability and co-immobilization.
In the present work, co-immobilization of cholesterol oxidase (COD) and horseradish peroxidase (POD) on perlite surface was attempted. The surface of perlite were activated by 3-aminopropyltriethoxysilane and covalently bonded with COD and POD via glutaraldehyde. Enzymes activities have been assayed by spectrophotometric technique. The stabilities of immobilized COD and POD to pH were higher than those of soluble enzymes and immobilization shifted optimum pH of enzymes to the lower pH. Heat inactivation studies showed improved thermostability of the immobilized COD for more than two times, but immobilized POD was less thermostable than soluble POD. Also activity recovery of immobilized COD was about 50% since for immobilized POD was 11%. The K(m) of immobilized enzymes was found slightly lower than that of soluble enzymes. Immobilized COD showed inhibition in its activity at high cholesterol concentration which was not reported for soluble COD before. Co-immobilized enzymes retained 65% of its initial activity after 20 consecutive reactor batch cycles.
Torabi
Seyed-Fakhreddin
SF
Department of Biotechnology, University College of Science, University of Tehran, Tehran, Iran. ftorabi@khayam.ut.ac.ir
Khajeh
Khosro
K
Ghasempur
Salehe
S
Ghaemi
Nasser
N
Siadat
Seyed-Omid Ranaei
SO
D000537:Aluminum Oxide / Q000737:chemistry*; D002789:Cholesterol Oxidase / Q000737:chemistry / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism*; D017743:Equipment Reuse; D005976:Glutaral / Q000494:pharmacology; D006735:Horseradish Peroxidase / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D008958:Models, Molecular; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012995:Solubility; D013696:Temperature
D003432:Cross-Linking Reagents; D004800:Enzymes, Immobilized; D012821:Silanes; C003076:Perlite; D012822:Silicon Dioxide; D002789:Cholesterol Oxidase; D006735:Horseradish Peroxidase; D000537:Aluminum Oxide; D005976:Glutaral