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Subsite mapping of human salivary α‐amylase and the mutant Y151M
Author(s) -
Kandra Lili,
Gyémánt Gyöngyi,
Remenyik Judit,
Ragunath Chandran,
Ramasubbu Narayanan
Publication year - 2003
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/s0014-5793(03)00495-2
Subject(s) - chemistry , stereochemistry , aglycone , mutant , binding site , cleavage (geology) , substrate (aquarium) , homologous series , biochemistry , crystallography , biology , paleontology , ecology , glycoside , fracture (geology) , gene
This study characterizes the substrate‐binding sites of human salivary α‐amylase (HSA) and its Y151M mutant. It describes the first subsite maps, namely, the number of subsites, the position of cleavage sites and apparent subsite energies. The product pattern and cleavage frequencies were determined by high‐performance liquid chromatography, utilizing a homologous series of chromophore‐substituted maltooligosaccharides of degree of polymerization 3–10 as model substrates. The binding region of HSA is composed of four glycone and three aglycone‐binding sites, while that of Tyr151Met is composed of four glycone and two aglycone‐binding sites. The subsite maps show that Y151M has strikingly decreased binding energy at subsite (+2), where the mutation has occurred (−2.6 kJ/mol), compared to the binding energy at subsite (+2) of HSA (−12.0 kJ/mol).