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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #108058
Title: MASS SPECTROMETRIC DETERMINATION OF DIOXYGEN BOND SPLITTING IN THE "PEROXY"INTERMEDIATE OF CYTOCHROME C OXIDASE

Author
item FABIAN, MARIAN - RICE UNIVERSITY
item Wong, William
item GENNIS, ROBERT - UNIVERSITY OF ILLINOIS
item PALMER, GRAHAM - RICE UNIVERSITY

Submitted to: Proceedings of the National Academy of Sciences (PNAS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: We wanted to find the mechanism underlying a specific enzymatic reaction. We used stable isotopes in a modern technique known as mass spectrometry to determine the answer. Our results confirmed the hypothesis that during this particular chemical reaction, the bond between the two oxygen atoms involved is broken. That fact could not be demonstrated previously, using other types of technology. This is one example of the analytical achievements in basic science that are now possible through the creative utilization of stable isotopes.

Technical Abstract: The "peroxy" intermediate (P form) of bovine cytochrome c oxidase was prepared by reaction of the two-electron reduced mixed-valence CO complex with 18O2 after photolytic removal of CO. The water present in the reaction mixture was recovered and analyzed for 18O enrichment by mass spectrometry. It was found that approximately one oxygen atom (18O) per one equivalent of fthe P form was present in the bulk water. The data show that the oxygen- oxygen dioxygen bond is already broken in the P intermediate and that one oxygen atom can be readily released or exchanged with the oxygen of the solvent water.