Effect of trypsin on the kinetic properties of reconstituted beef heart cytochrome c oxidase.
Isolated beef heart cytochrome c oxidase was reconstituted in liposomes by the cholate dialysis method with 85% of the binding site for cytochrome c oriented to the outside. Trypsin cleaved specifically subunit VIa and half of subunit IV from the reconstituted enzyme. The kinetic properties of the reconstituted enzyme were changed by trypsin treatment if measured by the spectrophotometric assay but not by the polarographic assay. It is concluded that subunit VIa and/or subunit IV participate in the electron transport activity of cytochrome c oxidase.
D000818:Animals; D002417:Cattle; D003576:Electron Transport Complex IV / Q000378:metabolism*; D007700:Kinetics; D008081:Liposomes / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology*; D013379:Substrate Specificity; D013997:Time Factors; D014357:Trypsin / Q000494:pharmacology*
D008081:Liposomes; D003576:Electron Transport Complex IV; D014357:Trypsin