Reaction: linear α-glucan = (n-1) 1,5-anhydro-D-fructose + D-glucose
For diagram of reaction click here.
Other name(s): α-(1→4)-glucan 1,5-anhydro-D-fructose eliminase; α-1,4-glucan exo-lyase; α-1,4-glucan lyase; GLase
Systematic name: (1→4)-α-D-glucan exo-4-lyase (1,5-anhydro-D-fructose-forming)
Comments: The enzyme catalyses the sequential degradation of (1→4)-α-D-glucans from the non-reducing end with the release of 1,5-anhydro-D-fructose. Thus, for an α-glucan containing n (1→4)-linked glucose units, the final products are 1 glucose plus (n-1) 1,5-anhydro-D-fructose. Maltose, maltosaccharides and amylose are all completely degraded. It does not degrade (1→6)-α-glucosidic bonds and thus the degradation of a branched glucan, such as amylopectin or glycogen, will result in the formation of 1,5-anhydro-D-fructose plus a limit dextrin. The other enzymes involved in this pathway are EC 220.127.116.11 (aldos-2-ulose dehydratase), EC 18.104.22.168 (1,5-anhydro-D-fructose dehydratase) and EC 22.214.171.124 (ascopyrone tautomerase).
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, UM-BBD, CAS registry number: 148710-18-3
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