The hydrolysis of phosphotyrosine esters in proteins is catalyzed by a family of enzymes

Chapter 25, Problem 25.12

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The hydrolysis of phosphotyrosine esters in proteins is catalyzed by a family of enzymes called protein phosphotyrosine phosphatases. H2O protein tyrosine phosphatase H2C OH a phosphorylated tyrosine residue in a protein a tyrosine residue in a protein phosphate O O O H2C P O HO O O P protein protein O These hydrolyses in many cases involve phosphoenzyme intermediates. The nucleophilic group of the phosphatase (the enzyme) is the thiol group of a cysteine residue in the active site. O NH H C C CH2SH a cysteine residue in protein a protein protein Using abbreviated structures like the ones in Eq. 25.22, write a curved-arrow mechanism for the hydrolysis that includes the structure of the phosphoenzyme intermediate. Assume that acids and bases are present in the enzyme active site as needed.