[The study of the active site of cytochrome P-450 LM2 using the chemical modification of tyrosine residues by tetranitromethane].

Selective chemical modification of the hemoprotein by tetranitromethane was used in order to elucidate the functional role of tyrosine residues in the cytochrome P-450 LM2 molecule. It was shown that the degree of cytochrome P-450 LM2 modification can be determined, using the second derivative of the UV absorption spectra. Modification of one tyrosine residue resulted in the inactivation of cytochrome P-450 LM2. Nitration of the cytochrome was accompanied by changes in the spectral properties of the hemoprotein with the formation of spectra typical of hyperporphyrin structures, thus suggesting the involvement of tyrosine residues in the formation of the active center of cytochrome P-450 LM2.