Frontier dextrins
Border dextrins are dextrins that are produced when branched polysaccharides ( starch or glycogen ) are broken down by various enzymes . These enzymes are not able to completely split the polysaccharides into the basic building blocks of maltose and glucose , as these have mixed glycosidic bonds .
Internationally, a division into α, β and φ limit dextrins is common, depending on whether digestion is carried out beforehand with α, β amylase or with phosphorylase .
When amylopectin is broken down, a distinction is made between three limit dextrins:
- The enzyme β-amylase ( emulsin ) creates a dextrin that needs maltase for further breakdown (border dextrin I).
- The cleavage by maltase produces another dextrin, which can now be cleaved again by β-amylase (border dextrin II).
- The resulting molecule can only be broken down by isoamylases , which only occur in plants and bacteria and can dissolve the α-1,6'-glycosidic compound, or by the debranching enzyme (border dextrin III).
See also
swell
- Wikibooks: Biochemistry and Pathobiochemistry: Glycogenolysis and Starch Breakdown # Breakdown of Chain Branches - Learning and Teaching Materials
- Entry of border dextrins in the Roche Medical Lexicon
- Meyer: About the constitution of amylopectin , in: Naturwissenschaften , p. 565
Individual evidence
- ↑ Bertoft E and Mäkelä J: Structure of Limit Dextrins from Storage Polysaccharides: a Comparison between Amylopectin and Glycogen . In: Yuryev VP, Tomasik P, Bertoft E (Eds.): Starch: achievements in understanding of structure and functionality . Nova Publishers, 2006, ISBN 1-60021-227-1 , chap. 4 , p. 87 ff .
- ↑ Lexicon of Biology: Debranching-Enzym