Chemical modification of tyrosine residues at the active centre of cytochrome P-450 CAM.

Soluble cytochrome P-450 CAM from Pseudomonas putida (EC 1.14.14.1) was chemically modified with tetranitromethane. At least five out of totally nine tyrosine residues are accessible to nitration as shown by tryptic peptide mapping using HPLC. Modification in the presence of the inhibitor metyrapone and subsequent peptide mapping indicate the location of one tyrosine residue at the active centre of cytochrome P-450 CAM.