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Involvement of alanine 103 residue in kinetic and physicochemical properties of glucose isomerases from Streptomyces species
Author(s) -
Borgi Mohamed Ali,
Rhimi Moez,
Bejar Samir
Publication year - 2007
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.200600085
Subject(s) - glucose 6 phosphate isomerase , isomerase , enzyme kinetics , streptomyces , chemistry , residue (chemistry) , enzyme , alanine , biochemistry , catalysis , streptomycetaceae , kinetics , stereochemistry , actinomycetales , biology , active site , amino acid , genetics , physics , quantum mechanics , bacteria
The Ala103 to Gly mutation, introduced within the glucose isomerase from Streptomyces sp. SK (SKGI) decreased its catalytic efficiency ( k cat / K m ) toward D ‐glucose from 7.1 to 3 mM –1 min –1 . The reverse counterpart replacement Gly103Ala introduced into the glucose isomerase of Streptomyces olivochromogenes (SOGI) considerably improved its catalytic efficiency to be 6.7 instead of 3.2 mM –1 min –1 . This later mutation also increased the half‐life time of the enzyme from 70 to 95 min at 80°C and mainly modified its pH profile. These results provide evidence that the residue Ala103 plays an essential role in the kinetic and physicochemical properties of glucose isomerases from Streptomyces species.