Mx. Qian et al., Enzyme-catalyzed condensation reaction in a mammalian alpha-amylase. High-resolution structural analysis of an enzyme-inhibitor complex, BIOCHEM, 40(25), 2001, pp. 7700-7709
Mammalian alpha -amylases catalyze the hydrolysis of cr-linked glucose poly
mers according to a complex processive mechanism. We have determined the X-
ray structures of porcine pancreatic alpha -amylase complexes with the smal
lest molecule of the trestatin family (acarviosine-glucose) which inhibits
porcine pancreatic alpha -amylase and yet is not hydrolyzed by the enzyme.
A structure analysis at 1.38 Angstrom resolution of this complex allowed fo
r a clear identification of a genuine single hexasaccharide species compose
d of two alpha -1,4-linked original molecules bound to the active site of t
he enzyme. The structural results supported by mass spectrometry experiment
s provide evidence for an enzymatically catalyzed condensation reaction in
the crystal.