Mixed-linked glucan

Although many 0-1,4-glucan endo-hydrolases have been examined, the ability to hydrolyze the 1,3 1,4 mixed-linked glucans has been investigated in detail only for a Streptomyces preparation (163,169,193), for a purified Aspergillus niger enzyme (45, 46), and for a fraction from a Trichoderma viride preparation (97). In each case the nature of the products (see Table IV) makes it clear that 4-0-glucosyl residues are... 

Mixed-linked Glucan P-l,3-glucosyl-(P-1,4-glucose )j None... 

Another group of p-glucanases, fmmd in plants and their seeds, hydrolyze P-l,3-linked glucans" and, in some cases, also mixed 1,3- and 1,4-linked polysaccharides. A characteristic enzyme is fmmd in barley (Table 12-1)." " Similar enzymes are produced by some bacteria" and also by molluscs." ... 

Mixed linked P-glucan is synthesized by (l-3),(l-4)-P-glucan synthase which is located in the Golgi apparatus and consists of two glycotransferases. One transferase primarily synthesizes cellotetrasyl units and the other synthesizes cellotriosyl units [65]. 

Hemicelluloses from annual plants (cereals crops) are mainly of the xy-lan type mixed-linked j6-l,3-l,4 glucans are also found. The structure has been... 

Aman, P, Graham, H. Analysis of total and insoluble mixed-linked (1 —> 3), (1 4) - p-D-Glucans in barley and oats. J. Agric. Food Chem. 35, 704 (1987) Amend, T., Belitz, H.-D. Gluten formation studied by the transmission electron microscope. Z. Lebensm. Enters. Forsch. 191, 184 (1990)... 

Villemez and coworkers have also reported that an enzyme preparation from mung beans could produce an alkali-insoluble D-glucan from UDP-D-glucose that contains both )8-D-(l — 3)- and )8-D-(l — 4)-links. However, it was not determined whether the product was a mixture of cellulose and callose or a single polysaccharide having mixed linkages. 

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