CYTOCHROME-P-450 - HEXAMERIC STRUCTURE OF THE PURIFIED LM4 FORM

Purified cytochrome P-450LM4 was found to be monodisperse in 20% glyce rol by analytical ultracentrifugation. Its S20,w value was quite simil ar to that of hexameric P450LM2. At lower glycerol concentrations the P450LM4 oligomers showed a tendency to aggregate. The P-450LM4 oligome rs were immobilized on Ultrogel A4 under conditions allowing only one covalent link to the matrix per oligomer. In the presence of SDS, the oligomers dissociated leaving only 1/6th of the initial amount of boun d protein on the matrix, suggesting that the purified P-450LM4 is a he xamer. This was confirmed by electron microscopy. The quaternary struc ture of the P-450LM4 was similar to that demonstrated earlier for P-45 0LM2.