Use of Natural Substrates and Enzymes

It is equally important to work with full-length versions of enzymes whenever this is feasible. Some enzymes are expressed naturally as multidomain proteins in which the catalytic machinery is localized to a single, discrete protein domain. In 

Thus recombinant enzyme constructs for use in activity assays should be designed to faithfully reflect the physiological state of the enzyme to the extent that is practical in vitro. 

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