Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1926703 | Archives of Biochemistry and Biophysics | 2008 | 8 Pages |
l-DOPA-2,3-dioxygenase from Streptomyces lincolnensis is a single-domain type I extradiol dioxygenase of the vicinal oxygen chelate superfamily and catalyzes the second step in the metabolism of tyrosine to the propylhygric acid moiety of the antibiotic, lincomycin. S. lincolnensisl-DOPA-2,3-dioxygenase was overexpressed, purified and reconstituted with Fe(II). The activity of l-DOPA-2,3-dioxygenase was kinetically characterized with l-DOPA (KM = 38 μM, kcat = 4.2 min−1) and additional catecholic substrates including dopamine, 3,4-dihydroxyhydrocinnamic acid, catechol and d-DOPA. 3,4-Dihydroxyphenylacetic acid was characterized as a competitive inhibitor of the enzyme (Ki = 2.2 mM). Site-directed mutagenesis and its effects on enzymatic activity were used to identify His14 and His70 as iron ligands.