A-l,6-Glucan

Glucoamylase (amyloglucosidase) Hydrolysis of terminal a-1,4- and a-l,6-glucan bonds in polysaccharides (starch, glycogen, etc.), yielding glucose (dextrose). 

Leuconostoc mesenteroides, Streptobacterium dextranicum, Streptococcus mutans and some other bacteria produce extracellular dextran from saccharose with the help of a-l,6-glucan D-fruc-tose-2-glucosyl transferase (dextran sucrase, EC 2.4.1.5). 

Dextran is an a-l,6-glucan (Formula 4.164 molecular weight Mr = 4—5 x 10 dal) with several glucose side chains, which are bound to the main chain of the macromolecule primarily through 1,3-linkages but, in part, also by 1,4- and 1,2-linkages. 

PuUulan [9057-02-7] first described in detail in 1959, is a water-soluble extracellular a-D-glucan elaborated by the fungus yiureobasidiumpullulans (formerly Eullulariapullulans) (285). It is a linear polymer of maltotriose units linked from the reducing end of one trisaccharidic unit to the nonreducing end of the next trisaccharidic unit by a(l — 6) linkages (286) ... 

Sanjuan R., Zueco J., Stock R., Font de Mora J. Sentandreu R. (1995) Identification of glucan-mannoprotein complexes in the cell wall of Candida albicans using a monoclonal antibody that reacts with a (l,6)-/3-glucan epitope. Mzcroftzo/ogy, 141, 1545-1551. 

S. Kralj, G. H. van Geel-Schutten, H. Rahaoui, R. J. Leer, E. J. Faber, M. J. van der Maarel, and L. Dijkhuizen, Molecular characterization of a novel glucosyltransferase from Lactobacillus reuteri strain 121 synthesizing a unique, highly branched glucan with a-(l —>4) and a-(l —>6) glucosidic bonds, Appl. Environ. Microbiol, 68 (2002) 4283 1291. 

Brown BI, Brown DH (1966) a-l,4-Glucan 6-glycosyltransferase from mammalian muscle. Methods Enzymol 8 395-403... 

A number of dextrans have been examined with a pig-spleen a-D-glucosidase.437 This enzyme could differentiate exterior a-(l - 2) linkages, because it readily hydrolyzed a-(l - 3) and a-(l - 6), but more slowly split a-(l- 2), linkages in the glucans. 

N. K. Kochetkov, N. N. Malysheva, E. M. Klimov, and A. V. Demchenko, Synthesis of polysaccharides with 1,2-c -glycosidic linkages by tritylthiocyanate polycondensation. Stereoregular a-(l-6)-D-glucan, Tetrahedron Lett., 33 (1992) 381-384. 

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