title: Solid-phase enzyme modification via affinity chromatography.
abstract: In the present study antileukemic enzyme L-asparaginase (ASNase) and catalase (as a model enzyme) were modified in solid-phase with activated polyethylene glycol (PEG(2)) by using ligand-immobilized affinity column systems L-asparagine-Sepharose CL-4B and Procion red-Sepharose CL-4B, respectively. Studies on change of specific activity with modification time showed negligible differences between batches of modified catalase. Modification of ASNase for 1 h resulted in 50.2% recovery of the specific activity and the attachment of 69 molecules of PEG(2) per molecule of ASNase forming 'PEGylated ASNase'. Sequential modification of ASNase by activated PEG and heparin resulted in coupling of about nine molecules of heparin per molecule of PEGylated ASNase. Intravenous (i.v.) administration of PEG(2)-modified ASNase showed prolonged presence in the blood circulation and no adverse effects or symptoms of anaphylaxis were observed in presensitized mice.
authors.affiliation: Department of Biological Sciences, Middle East Technical University, 06531 Ankara, Turkey.
authors.forename: Erkan Türker
authors.initials: ET
authors.lastname: Baran
authors.forename: Nazmi
authors.initials: N
authors.lastname: Ozer
authors.forename: Vasif
authors.initials: V
authors.lastname: Hasirci
mesh_terms: D000818:Animals; D001215:Asparaginase / Q000008:administration & dosage / Q000097:blood / Q000737:chemistry / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism*; D002846:Chromatography, Affinity / Q000379:methods*; D051379:Mice; D011092:Polyethylene Glycols / Q000737:chemistry
chemical_list: D011092:Polyethylene Glycols; D002374:Catalase; D001215:Asparaginase