Storage Polysaccharides
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STORAGE POLYSACCHARIDES Mrs. B. Dorka Vijaya Kumari Asst. Prof. in Biochemistry Govt. College for women (A), Guntur Polysaccharides Storage Muco Polysaccharides Structural Polysaccharides Polysaccharides Starch Glycogen Inulin Cellulose Pectin Chitin Chondroi Heparin Hyaluron tin ic acid Sulfate M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur STORAGE POLYSACCHARIDES • These are sugars which store reserve food material in plants & animals. Ex: . Starch in plants . Glycogen in animals . Inulin in some plants. M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur STARCH • Homopolymer of Glucose. • Reserve food material in plants. • Arranged in concentric layers in the grains. • When boiled, the central part dissolves and passes out. • This soluble part is “Amylose”. STARCH M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur • Insoluble portion is “amylopectin". It absorbs water & swells. • Starches generally contain 10-20% Amylose & 80-90% Amylopectin. • Starch on complete hydrolysis gives Glucose & partial hydrolysis gives maltose. STARCH M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur http://www.biologydiscussion.com/eukaryotic-cell/notes-on-cell-inclusions-with-diagram/6004 M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur S T A R MRS. B. DORKA, ASST. PROF. IN BIOCHEMISTRY, GCW(A), C GUNTUR http://www.periodni.com/gallery/starch.png H STRUCTURE & PROPERTIES • Starch is a polymer of Glucose. • α- D- glucose units are linked by α (1→4) linkage. • Amylose is an unbranched chain. • Amylopectin is branched. It has α (1→4) & α (1→6) linkage also. STARCH Mrs. B. Dorka, Asst. Prof. In Biochemistry, GCW(A), Guntur • Amyloses gives blue-black colour with Iodine. • Amylopectin gives violet-red colour with Iodine. • “Amylases” are the enzymes that hydrolyze starch. • Amylases act on starch & gives maltose. STARCH M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur https://ketopentose.files.wordpress.com/2013/02/starch.jpg M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur GLYCOGEN • A storage polysaccharide in animals. • Homoglycan, made of D- Glucose units. • D- Glucose units are joined by α (1→4) and α (1→6) glycoside bonds like that of amylopectin. GLYCOGEN M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur Structure Of Glycogen http://www.periodni.com/gallery/download_image.php?name=glycogen.png • Glycogen is more branched than amylopectin. • Stored in liver & muscle in compact form. • Glycogen particles are spherical in shape. • Acts as reserve food material during fasting GLYCOGEN M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur INULIN • Inulin is a storage polysaccharide found is tubers of chicory, Dahlia and in the bulb of Onion. • A white crystalline powder. • Made of D – Fructose units. • Very easily hydrolyzed by acids. • Readily soluble in hot water. • Doesn’t give characteristic colour with Iodine. INULIN M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur Structure of Inulin http://www.dynamicscience.com.au/tester/solutions1/chemistry/foodchemistry/inulin.htm • Inulin is hydrolyzed by inulinase. • It is levorotatory. • It is an unbranched structure. • Linkage is β (1 →2) between two fructose units. • Inulin is used as commercial source of fructose. INULIN M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur Points to Remember: . The sugars which store reserve food material in plants and animals are Storage Poly saccharides. Ex: Starch, Glycogen, Inulin etc . Starch is S.P.S in plants, composed of D- Glucose. Starch grain Contains Amylose α (1→4) & Amylopectin is α (1→4) & α (1→6). Glycogen is S.P.S in animals, composed of D- Glucose. Structure is similar to starch, but with extensive branching with both α (1→4) & α (1→6) linkages. Inulin is S.P.S in some plants, composed of D- Fructose linked by β (1 →2) . Used as commercial source of fructose Gist M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur M r s . B . D o r k a , Asst. Prof. In Biochemistry, GCW(A), Guntur .