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Maloshenok L. G., Uporov I. V., Ugarova N. N.
Catalytic Properties and Bioluminescence Spectra of Recombinant
Luciferase of Fire-Fly Luciola Mingrelica with Point Mutations Exterior
to Active Site
Abstract
Mutants with substitutions His433Asn, His433Ser have been made by means
of site-directed mutagenesis technique. We studied catalytic properties of the
enzyme mutant forms and their bioluminescence spectra. The values of KM,
LH2 were equal for the recombinant luciferase and both of the mutants,
whereas the KM, ATP increased by 20 % for the His433Asn mutant and
by 50 % for the His433Ser mutant. Thus, the mutations decreased the
affinity of the enzyme to ATP. The specific activity of the luciferase
decreased by 20 % for the His433Asn mutant. The His433Ser mutation
resulted in dramatic decrease in the specific activity (200 times). Analysis of
the data obtained permitted us to elucidate the mechanism of the influence of
the His433 residue on the luciferase active site.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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