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  • Title: Purification and partial characterization of an amino acid alpha,beta- dehydrogenase, L-tryptophan 2',3'-oxidase from Chromobacterium violaceum.
    Author: Genet R, Denoyelle C, Ménez A.
    Journal: J Biol Chem; 1994 Jul 08; 269(27):18177-84. PubMed ID: 8027079.
    Abstract:
    L-Tryptophan 2',3'-oxidase is a novel enzyme that specifically catalyzes the alpha,beta-dehydrogenation of L-tryptophan derivatives. It was extracted from Chromobacterium violaceum and purified 108-fold to apparent homogeneity with a 34% overall recovery. The molecular weight of the native enzyme is approximately 680,000, and its isoelectric point is nearly equal to 4. SDS-polyacrylamide gel electrophoresis showed that the enzyme is composed of two components with molecular weight of approximately 74,000 and 14,000. It also contains a noncovalently bound heme prosthetic group, as judged from a typical spectrum showing maxima at 427, 530, and 560 nm. The catalyzed reaction is completed without side-product formation over a broad pH range comprised between 3 and 8. The enzyme is reoxidized at the expense of molecular oxygen by producing one molecule of H2O2. Kinetic parameters for modification of N-acetyl-L-tryptophanamide were determined (Km = 19.5 microM; kcat = 45.2 s-1). A Hill coefficient of about 1 suggests the absence of any cooperative effect. As inferred from both its kinetic and stability optimal conditions, L-tryptophan 2',3'-oxidase constitutes a promising tool for chemical modification of tryptophanyl side chain in peptides and proteins.
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