title: Catalytic action of L-methionine gamma-lyase on selenomethionine and selenols.
abstract: We examined the catalytic action of L-methionine gamma-lyase (EC 4.4.1.11) on selenomethionine (2-amino-4-(methylseleno)butyric acid), methaneselenol, l-hexaneselenol, and benzeneselenol. The enzyme catalyzes alpha, gamma-elimination of selenomethionine to yield alpha-letobutyrate, ammonia, and methaneselenol, and also its gamma-replacement reaction with various thiols to produce S-substituted homocysteines. Selenomethionine is an even better substrate than methionine in alpha, gamma-elimination but is less effective in gamma-replacement. In addition, L-methionine gamma-lyase catalyzes gamma-replacement reaction of methionine and its derivatives with selenols to form the corresponding Se-substituted selenohomocysteines, although selenols are less efficient substituent donors than thiols. This is the first proven mechanism for the incorporation of selenium atom into amino acids.
mesh_terms: D001555:Benzene Derivatives; D013437:Carbon-Sulfur Lyases / Q000378:metabolism*; D000441:Hexanols; D007700:Kinetics; D008190:Lyases / Q000378:metabolism*; D000432:Methanol / Q000031:analogs & derivatives; D008715:Methionine; D016566:Organoselenium Compounds; D010636:Phenols; D011485:Protein Binding; D011549:Pseudomonas / Q000201:enzymology; D012643:Selenium; D012645:Selenomethionine; D013053:Spectrophotometry; D013379:Substrate Specificity
chemical_list: D001555:Benzene Derivatives; D000441:Hexanols; D016566:Organoselenium Compounds; D010636:Phenols; C019003:methaneselenol; C018846:benzeneselenol; D012645:Selenomethionine; D008715:Methionine; D008190:Lyases; D013437:Carbon-Sulfur Lyases; C021558:L-methionine gamma-lyase; D012643:Selenium; D000432:Methanol