Models for depolymerizing enzymes. Application to α‐amylases

Several research groups have explored the action pattern of depolymerizing enzymes by examining the distribution of products during the early stages of digestion. Mathematical models for the various mechanisms that have been proposed for the behaviour of depolymerizing enzymes are developed in this paper. Published data for several amylases are reexamined in light of this theoretical analysis. It is concluded that following an initial random attack on a long polymer substrate, the enzyme frequently releases only one of the substrate fragments. The retained fragment may be repetitively hydrolyzed near one end to release a series of oligosaccharides before the enzyme substrate–fragment complex finally dissociates. Near optimum conditions Bacillus subtilis (var. amyloliquefaciens) amylase is unique among the enzymes tested because it does not repetitively attack substrate fragments.