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Molecular Characterization of Beef Liver Catalase by Scanning Tunneling Microscopy
Author(s) -
Zhang Jingdong,
Chi Qijin,
Zhang Bailin,
Dong Shaojun,
Wang Erkang
Publication year - 1998
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/(sici)1521-4109(199809)10:11<738::aid-elan738>3.0.co;2-d
Subject(s) - scanning tunneling microscope , catalase , molecule , highly oriented pyrolytic graphite , materials science , chemistry , graphite , adsorption , analytical chemistry (journal) , nanotechnology , crystallography , organic chemistry , enzyme
Beef liver catalase molecules can stick tenaciously to the highly oriented pyrolytic graphite (HOPG) surface which has been activated by electrochemical anodization. The immobilized sample is stable enough for high resolution scanning tunneling microscope (STM) imaging. When the anodized conditions are controlled properly, the HOPG surface will be covered with a very thin oxide layer which can bind the protein molecules. Individual molecules of native beef liver catalase are directly observed in detail by STM, which shows an oval‐shape structure with a waist. The dimensions of one catalase molecule in this study are estimated as 9.0 × 6.0 × 2.0 nm 3 , which are in good agreement with the known data obtained from X‐ray analysis, except the height can not be exactly determined from STM. Electrochemical results confirm that the freshly adsorbed catalase molecules maintain their native structures with biological activities. However, the partly unfolding structure of catalase molecules is observed after the sample is stored for 15 days, this may be caused by the long‐term interaction between catalase molecules and the anodized HOPG surface.