Excitation Energy Transfer Study of the Spatial Relationship Between the Carbonyl and Metal Cofactors in Pig Plasma Amine Oxidase
Abstract
Nine-Hydrazinoacridine irreversibly labeled pig plasma amine oxidase by covalent attachment ot the active carbonyl cofactor. The visible absorption of the modified protein displays new absorption bands at 495 and 525 nm. Its emission spectrum exhibited maxima at 415 and 440 nm. In addition, both absorption and emission spectra were insensitive to pH changes between 6 and 10. Phase modulation fluorometry was used to determine fluorescence lifetimes of zinc (2+) and cobalt (2+) substituted acridinyl plasma amine oxidase. Energy transfer efficiency was 22%; the distance separating the cobalt (2+) ion (in the copper binding site) and the acridine moiety (the amine substrate binding site) ranges between 11.7 and 14.7 A. This work defines the proximity of the metal and substrate (and hence the carbonyl cofactor) and precludes any direct interaction between copper (2+) and pyrroloquinoline quinone or between copper (2+) and the substrate. Keywords: Dimers, Reprints.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 15, 1988
- Accession Number
- ADA200839
Entities
People
- Mark S. Lamkin
- Michael C. Falk
- Taffy J. Williams
Organizations
- Naval Medical Research Center