title: Purification and characterization of liver catalase in acatalasemic beagle dog: comparison with normal dog liver catalase.
abstract: Catalase from acatalasemic dog liver was purified to homogeneity and its properties were compared with those of normal dog liver catalase. The purified acatalasemic and normal dog liver catalases were found to have the same molecular weight (230,000 Da) and isoelectric point (pI: 6.0-6.2) and both enzymes contained four hematins per molecule. The catalytic activity of catalase from acatalasemic dog was normal. Furthermore, there was no difference between the acatalasemic and normal dog catalases in the binding affinity to NADPH (apparent Kd: 0.11-0.12 microM) and in the sensitivity to oxidative stress by hydrogen peroxide, the normal substrate of catalase. The acatalasemic dog enzyme was stable only in a narrow pH range (pH 6-9) although the normal enzyme was stable in a wide pH range (pH 4-10). Acatalasemic dog liver catalase also showed a slight low thermal stability at 37 degrees C and the heat-lability was remarkable at 45 degrees C, compared to the normal dog enzyme. These results indicated that the acatalasemic dog catalase is catalytically normal although it is associated with an unstable molecular structure.
authors.affiliation: Analytical and Metabolic Research Laboratories, Sankyo Co., Ltd., Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: M
authors.initials: M
authors.lastname: Watanabe
authors.forename: Y
authors.initials: Y
authors.lastname: Sasaki
authors.forename: T
authors.initials: T
authors.lastname: Ikeda
mesh_terms: D020642:Acatalasia / Q000201:enzymology*; D000818:Animals; D002374:Catalase / Q000302:isolation & purification / Q000378:metabolism*; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D006420:Hemeproteins / Q000737:chemistry / Q000235:genetics; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D009249:NADP / Q000378:metabolism; D018384:Oxidative Stress; D011485:Protein Binding; D013696:Temperature
chemical_list: D006420:Hemeproteins; D009249:NADP; D006861:Hydrogen Peroxide; D002374:Catalase