Polysaccharides: Difference between revisions

<scene name='Polysaccharides/9_5_amylopectin1/1'>Amylopectin</scene> is also a large glucose polymer that has α(1→4) glycosidic bonds connecting the glucose units, but it also contains α(1→ 6) glycosidic bonds. In this scene the main branch is colored yellow, the side branch is green and the oxygen atoms of the α(1→4) bonds are red. Rotate <scene name='Polysaccharides/9_5_amylopectin1a/2'>Amylopectin</scene> to view the glucopyranosyl units on edge and verify that the bonds are α linkages. <scene name='Polysaccharides/9_5_amylopectin2/2'>Glucose unit four</scene>, branching point, colored yellow with the oxygen atom connecting C-6 of unit four to the C-1 of the side chain colored green. The <scene name='Polysaccharides/9_5_amylopectin3/1'>reducing terminus</scene> is colored CPK, C-1 of this unit is able to open to the aldehyde and function as a reducing agent, but all the other termini of an amylopectin molecule are non-reducing because the C-1 of these terminal units are involved in glycosidic bond and can not form the aldehyde. In this scene the non-reducing termini are colore green. <scene name='Polysaccharides/20_5_10_main_cpk/3'>Looking down the axis</scene> of a 20-unit chain (colored CPK) having a 5-unit chain (green) branching at unit five and a 10-unit chain (yellow) branching at unit 10. The red atoms in the yellow and green branching chains are the oxygen atoms of the α(1→4) glycosidic bonds. Structure <scene name='Polysaccharides/20_5_10_main_cpk2/1'>rotated 90 deg</scene>. Notice that the helical structure is more open than the unbranched amylose and the previous structure having only one branch. The native amylopectin having many more branching points would be more open than this structure, in fact it would have very little curvature. Rotating & zooming amylopectin gives a focused view of the α(1→ 6) bond. <scene name='Polysaccharides/20_5_10_main_cpk/2'>TextToBeDisplayed</scene>