Analysis of the Roles of Amino Acid Residues in the Flavoprotein Tryptophan 2-monooxygenase Modified by 2-oxo-3-pentynoate: Characterization of His338, Cys339, and Cys511 Mutant Enzymes
Abstract
The flavoprotein tryptophan 2-monooxygenase catalyzes the oxidative decarboxylation of tryptophan to indoleacetamide. His338, Cys339, and Cys511 of the Pseudomonas savastanoi enzyme were previously identified as possible active-site residues by modification with 2-oxo-3-pentynoate ([G. Gadda, L.J. Dangott, W.H. Johnson Jr., C.P. Whitman, P.F. Fitzpatrick, Biochemistry 38 (1999) 5822-5828]). The H338N, C339A, and C511S enzymes have been characterized to determine the roles of these residues in catalysis. The steady-state kinetic parameters with both tryptophan and methionine decrease only slightly in the case of the H338N and C339A enzymes; the decrease in activity is greater for the C511S enzyme. Only in the case of the C511S enzyme do deuterium kinetic isotope effects on kinetic parameters indicate a significant change in catalytic rates. The structural bases for the effects of the mutations can be interpreted by identification of L-amino acid oxidase and tryptophan monooxygenase as homologous proteins, © 2002 Elsevier Science (USA), All rights reserved.
Recommended Citation
P. Sobrado and P. F. Fitzpatrick, "Analysis of the Roles of Amino Acid Residues in the Flavoprotein Tryptophan 2-monooxygenase Modified by 2-oxo-3-pentynoate: Characterization of His338, Cys339, and Cys511 Mutant Enzymes," Archives of Biochemistry and Biophysics, vol. 402, no. 1, pp. 24 - 30, Elsevier, Jun 2002.
The definitive version is available at https://doi.org/10.1016/S0003-9861(02)00063-2
Department(s)
Chemistry
Keywords and Phrases
Flavoprotein; Isotope effects; L-amino acid oxidase; Mutagenesis; Oxidase; Tryptophan monooxygenase
International Standard Serial Number (ISSN)
0003-9861
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2024 Elsevier, All rights reserved.
Publication Date
01 Jun 2002
PubMed ID
12051679
Comments
National Institutes of Health, Grant GM 58698