Studies on the Subsite Structure of Amylases

Publisher Website
Google Scholar
Abstract
The difference spectra of liquefying α-amylase [EC 3. 2. 1.1] from B. subtilis upon the addition of a slowly reacting substrate, maltotriose, were measured to investigate specific binding of the substrate to the enzyme. The spectra produced by maltotriose were attributed to one tryptophan and one tyrosine residues on the basis of analysis of their shape and magnitude. From the dependence of the difference absorption upon the concentration of maltotriose, the dissociation constant of the maltotriose-enzyme complex was determined to be 170(±20) mM, which is in good agreement with the Michaelis constant, Km obtained from the steady-state kinetics. The difference spectrum characteristic of a tryptophan residue was significantly decreased by the chemical modification of a tryptophan residue with N-bromosuc-cinimide.

This publication has 0 references indexed in Scilit: