Catalyzes the radical-mediated cleavage of tyrosine to 2-iminoacetate and 4-cresol. L-tyrosine + NADPH + S-adenosyl-L-methionine = 2-iminoacetate + 4-methylphenol + 5'-deoxyadenosine + L-methionine + NADP(+) Binds 1 [4Fe-4S] cluster per subunit. The cluster is coordinated with 3 cysteines and an exchangeable S-adenosyl-L-methionine. Cofactor biosynthesis; thiamine diphosphate biosynthesis. Forms a heterodimer with ThiG. The product 2-iminoacetate hydrates in vitro to yield glyoxylate and ammonium. Belongs to the radical SAM superfamily. ThiH family.