1.11.2.5	H191A	mutant loses ability to hydroxylate 3-methyl-L-tyrosine	
1.11.2.5	H274A	mutant loses ability to hydroxylate 3-methyl-L-tyrosine	
1.11.2.5	H313A	mutant loses ability to hydroxylate 3-methyl-L-tyrosine. Heme content of the mutant enzyme is very low, very little heme-Fe binding ability	
1.11.2.5	H317A	mutant loses ability to hydroxylate 3-methyl-L-tyrosine. Heme content of the mutant enzyme is very low, very little heme-Fe binding ability