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Site‐directed mutagenesis of the lower parts of the major substrate channel of yeast catalase A leads to highly increased peroxidatic activity
Author(s) -
Zamocky M.,
Herzog Ch.,
Nykyri L.M.,
Koller F.
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00568-t
Subject(s) - steric effects , mutagenesis , chemistry , destabilisation , yeast , mutant , saccharomyces cerevisiae , substrate (aquarium) , catalase , biochemistry , enzyme , site directed mutagenesis , saturated mutagenesis , stereochemistry , biology , gene , psychology , social psychology , ecology
Five single replacement mutants of catalase A from Saccharomyces cerevisiae were prepared (F148V, F149V, F156V, F159V, and V111A). The exchanges were expected to relieve steric constraints in the lowest part of the major substrate channel. The overall stability of the isolated enzymes is unaffected by the respective amino acid exchanges, but some modifications lead to decreased protohaem binding. All isolated mutants (most pronounced the V111A‐species) show decreased catalatic and markedly increased peroxidatic activity, both with aliphatic and aromatic substrates. These effects can in part be explained by steric effects, but also reveal destabilisation of compound I.