|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|5507067||1400310||2017||4 صفحه PDF||ندارد||دانلود کنید|
â¢Positive cooperativity of subunits in L-lysine Î±-oxidase was first shown.â¢The kinetic scheme of L-lysine deamination involving parallel-subsequent action of each subunit in the catalytic act was proposed.â¢The MichaelisâMenten constant has been estimated using the Hill coefficient and the equation developed for allosteric enzymes.â¢High selectivity and absolute L-stereospecificity of the enzyme were found.â¢L-Lysine conversion is inhibited by non-cleavable analogs of lysine as well as by the reaction product.
The present work aims to investigate the kinetic characteristics of homodimer enzyme L-lysine Î±-oxidase from Trichoderma cf. aureoviride Rifai VKM F-4268D, taking into account allosteric effects. The enzyme was first shown to reveal positive cooperativeness, h=2.05Â±0.15. Using additional opportunities of Hill coefficient the value of the MichaelisâMenten constant has been estimated, Km=1.015â10â5Ð, indicating high strength of substrate binding to the active site of each subunit. High selectivity and absolute L-stereospecificity of the enzyme were shown. The inhibition of L-lysine conversion by non-cleavable lysine analogs as well as the reaction product was found out to take place. These effects have been evaluated only as the inhibition coefficients (%). A more detailed study of these inhibition effects was complicated because of the cooperativeness of enzyme subunits mentioned above. The kinetic scheme of L-lysine Î±-oxidase was proposed involving parallel-subsequent action of each of two subunits in the catalytic act.We think that the results obtained will be useful for studying the kinetic properties of other multi-subunit enzymes and improve understanding of the mechanisms of their action.
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Journal: Biochemistry and Biophysics Reports - Volume 9, March 2017, Pages 9-12open access