The catalytic mechanism of alpha-amylases based upon enzyme crystal structures and model building calculations.
Based upon the known crystal structures of Taka-amylase A and the recently refined Porcine pancreatic alpha-amylase inhibitor complex a mechanism of catalysis in amylase active centers is proposed. The mechanism differs significantly from the well-known lysozyme model of catalysis. The hydrolysis is catalyzed by three carboxyl groups and its starts from a water nucleophilic attack and opening of the glucose ring in the catalytic center rather than from protonation of the glycosidic oxygen. The main supporting experimental observations are briefly discussed.
Mazur
A K
AK
Pacific Institute of Bioorganic Chemistry, Russian Academy of Sciences, Vladivostok.
Haser
R
R
Payan
F
F
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002384:Catalysis; D017124:Conserved Sequence; D003461:Crystallography; D004791:Enzyme Inhibitors / Q000737:chemistry; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry / Q000378:metabolism; D010179:Pancreas / Q000378:metabolism; D011487:Protein Conformation; D013552:Swine; D000516:alpha-Amylases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*
D004791:Enzyme Inhibitors; D000516:alpha-Amylases; D009113:Muramidase